Title of Invention	"AN IMPROVED PROCESS FOR THE PREPARATION OF PHOTOCURABLE COMPOSITIONS OF MODIFIED VISCOSITY FOR DRY RESIST APPLICATION"
Abstract	This invention relates to an improved process for preparation of photo-curable composition of modified changeable viscosity for dry resist application comprising mixing in an inert atmosphere a photocurable polymer solution as claimed in the expending application 813/DEL/2000 with an aliphatic amine such as hexyl amine, octyl amine, dodecyl amine at concentration of 1 to 10% for a period ranging from 10 to 30 minutes at a temperature of 25° to 30°C and collecting the resultant product in the form of solution.

Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF PHOTOCURABLE COMPOSITIONS OF MODIFIED VISCOSITY FOR DRY RESIST APPLICATION"

Abstract

This invention relates to an improved process for preparation of photo-curable composition of modified changeable viscosity for dry resist application comprising mixing in an inert atmosphere a photocurable polymer solution as claimed in the expending application 813/DEL/2000 with an aliphatic amine such as hexyl amine, octyl amine, dodecyl amine at concentration of 1 to 10% for a period ranging from 10 to 30 minutes at a temperature of 25° to 30°C and collecting the resultant product in the form of solution.

Full Text	This invention relates to an improved process for the preparation of photo-curable compositions with modified viscosity for dry resist application. More particularly, it relates to a process for the preparation of photo-curable compositions with improved viscosity for aqueous developable formulations. The polymer composition that were used for the process of this invention was copolymers with multifunctional groups developed in the copending application No.813/DEL/2000 of the applicants in which it has been described and claimed a process for the preparation of copolymers with multifunctional groups comprising mixing in a yellow light atmosphere a photo-curable polymer solution with an organic dye, a sensitizer, a crosslinking monomer and solvent The photo-curable compositions with improved viscosity thus prepared by the process of this invention are useful for transfer of image onto a printed circuit board or lithographic plate as dry resists. Dry resists are important imaging generation which are extensively used in the manufacture of wire boards and printed circuit boards. The dry resist essentially consists of a photocurable composition sandwiched between a polyester base sheet and a polyethylene cover foil. In applications, the cover foil is removed and the base sheet is laminated onto a copper clad insulating support The copper clad insulating support is then selectively exposed to UV source through a photomask. The photomask comprises of parts that are opaque and other transparent to UV source. The differential parts of the photomask thus transfer an image to the copper clad insulating support The photo-curable compositions with improved viscosity prepared as per the process of this invention, fall into the category of negative photoresists. In this category of photoresists, the areas exposed to UV source, become insoluble in a developing solution as a result of the photochemical reaction occurring during exposure to UV source. The unexposed areas are soluble in the developing solution and can be removed whereby an image is transferred to the copper clad insulating support. In the formulation of photo-curable composition, the essential ingredients are the polymer solution which normally consists of a tri, tetra polymer with composition of choice, a dye, a sensitizer, crosslinking monomer, photo-initiator, solvent. For hand lay up applications, the viscosity of the solution is not very critical. However, if the composition has to be used on a mechanical coating unit, the viscosity of the formulation becomes critical. If the right viscosity is not maintained the coating thickness would vary and the non-uniformity would pose problems in processing. The viscosity of the polymer solution as obtained from the reactor is not sufficient for mechanical coating applications and there is a need to improve the viscosity by suitable additives so that the viscosity can be adjusted to suit the mechanical device of choice. The known compositions available suffers from the disadvantage that the viscosity of the solution cannot be changed to suit the mechanical device of choice for getting a uniform film. Changes in the viscosity of the photo-curable composition should be made in such a way the resulting polymer can be readily used for photoresist formulations. The primary requirements for such applications are - 1. The polymer should contain carboxylic acid groups such that the polymer after exposure to UV source should be aqueous soluble. 2. The polymer should have sufficient mechanical strength so that during the processing stage, the film remains in tact. 3. The polymer should contain aromatic groups so that quantum efficiency during the photochemical reaction step is possible. 4. The glass temperature of the polymer should be close to ambient temperature. These characteristics should not be disturbed while improving the viscosity. The main object of the present invention is therefore to provide a process for the preparation of photo-curable compositions with improved viscosity. Another object of the present invention is to provide a process for the preparation of photo-curable compositions with improved viscosity so that die glass transition temperature and mechanical strength are not altered. Yet another object of the present invention is to provide a process for the preparation of photo-curable compositions with improved viscosity that does not disturb the photochemical reaction to give image of choice after developing. Accordingly, the present invention provides an improved process for preparation of photo-curable composition of modified changeable viscosity for dry resist application comprising mixing in an inert atmosphere a photocurable polymer solution as claimed in the copending application 813/DEL/2000 with an aliphatic amine such as hexyl amine, octyl amine, dodecyl amine at concentration of 1 to 10% for a period ranging from 10 to 30 minutes at a temperature of 25° to 30°C and collecting the resultant product in the form of solution. In one of the embodiments of the invention, the inert gas used may be nitrogen, argon. In another embodiment the aliphatic amine used may be haxylamine, octyl amine, dodacyl amine and the concentration used may be 0.1 to 0.05%. In still another embodiment of the present invention, the photo-curable formulation used may be prepared by mixing in an yellow light atmosphere, a photo-curable polymer solution with an organic dye, a sensitizer, photo-initiator, crosslinking monomar, solvent, for a period ranging from 20 to 60 minutes, at a temperature in the range of 25 to 35°C, till uniform consistency is achieved and collecting the product in the form of a solution. The process of the present invention is described with reference to following examples, which are illustrative only and should not be construed to limit the scope of this invention in any manner. EXAMPLE-1 In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.15 gms of octyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 15 minutes of reaction, was collected in the form of a solution. The yield obtained was 100 ml. EXAMPLE-2 In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.38 gins of octyl amine and solution was maintained isothermally at 35°C for 10 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 10 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml. Example 3 In an inert atmosphere of argon, to 150 ml of polymer solution was added 2.25 gms of octyl amine and solution was maintained isothermally at 30°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 150ml. EXAMPLE - 4 In an inert atmosphere of nitrogen, to 200 ml of polymer solutic n was added 1.5 gms of octyl amine and solution was maintained isothermally at 25°C for 30 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 30 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml. Example 5 In an inert atmosphere of argon, to 100 ml of polymer solution was added 0.25 gms of dodecyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 10 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml. EXAMPLE - 6 In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.55 gms of dodecyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 15 minutes of reaction, was collected in the form of a solution. The yield obtained was 100 ml. EXAMPLE - 7 In an inert atmosphere of nitrogen, to 150 ml of polymer solution was added 1.65 gms of octyl amine and solution was maintained isothermally at 30°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 150ml. EXAMPLE-8 In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.15 gms of octyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 10 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml. EXAMPLE - 9 In an inert atmosphere of nitrogen, to 200 ml of polymer solution was added 4.5 gms of dodecyl amine and solution was maintained isothermally at 25°C for 30 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 30 minutes of reaction, was collected in the form of a solution. The yield obtained was 200 ml. EXAMPLE - 10 In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.15 gms of hexyl amine and solution was maintained isothermally at 25°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 100 ml. EXAMPLE-11 In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.35 gms of hexyl amine and solution was maintained isothermally at 30°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 15 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml. EXAMPLE - 12 In an inert atmosphere of nitrogen, to 200 ml of polymer solution was added 2.4 gms of hexyl amine and solution was maintained isothermally at 35°C for 30 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 30 minutes of reaction, was collected in the form of a solution. The yield obtained was 202 ml. EXAMPLE - 13 In an inert atmosphere of nitrogen, to 150 ml of polymer solution was added 1.15 gms of hexyl amine and solution was maintained isothermally at 35°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 150ml. EXAMPLE - 14 IP iii inert atmosphere of nitrogen, to 200 ml of polymer solusion was added 2.15 gms of dodecyl amine and solution was maintained isothermally at 35°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 202 ml. Advantages of the present invention: 1. The photo-curable compositions with improved viscosity prepared by the process of this invention are aqueous developable. 2. The photo-curable compositions with improved viscosity obtained by the process of this invention can be directly used for the coating of film onto copper clad laminate in PCB industriesof dryresists. 3. The process of this invention is amenable for scale up operation. WE CLAIM 1. An improved process for preparation of photo-curable composition of modified changeable viscosity for dry resist application comprising mixing in an inert atmosphere a photocurable polymer solution as claimed in the copending application 813/DEL/2000 with an aliphatic amine such as hexyl amine, octyl amine, dodecyl amine at concentration of 1 to 10% for a period ranging from 10 to 30 minutes at a temperature of 25° to 30°C and collecting the resultant product in the form of solution. 2. A process as claimed in claim 1, wherein, the inert gas used may be nitrogen or argoa 3. A process for the preparation of photo-curable compositions with modified viscosity for dry resist application as substantially described with reference to the example.

Full Text

This invention relates to an improved process for the preparation of photo-curable compositions with modified viscosity for dry resist application. More particularly, it relates to a process for the preparation of photo-curable compositions with improved viscosity for aqueous developable formulations. The polymer composition that were used for the process of this invention was copolymers with multifunctional groups developed in the copending application No.813/DEL/2000 of the applicants in which it has been described and claimed a process for the preparation of copolymers with multifunctional groups comprising mixing in a yellow light atmosphere a photo-curable polymer solution with an organic dye, a sensitizer, a crosslinking monomer and solvent
The photo-curable compositions with improved viscosity thus prepared by the process of this invention are useful for transfer of image onto a printed circuit board or lithographic plate as dry resists.
Dry resists are important imaging generation which are extensively used in the manufacture of wire boards and printed circuit boards. The dry resist essentially consists of a photocurable composition sandwiched between a polyester base sheet and a polyethylene cover foil. In applications, the cover foil is removed and the base sheet is laminated onto a copper clad insulating support The copper clad insulating support is then selectively exposed to UV source through a photomask. The photomask comprises of parts that are opaque and other transparent to UV source. The differential parts of the photomask thus transfer an image to the copper clad insulating support
The photo-curable compositions with improved viscosity prepared as per the process of this invention, fall into the category of negative photoresists. In this category of photoresists, the areas exposed to UV source, become insoluble in a developing solution as a result of the photochemical reaction occurring during exposure to UV source. The unexposed areas are soluble in the

developing solution and can be removed whereby an image is transferred to the copper clad insulating support.
In the formulation of photo-curable composition, the essential ingredients are the polymer solution which normally consists of a tri, tetra polymer with composition of choice, a dye, a sensitizer, crosslinking monomer, photo-initiator, solvent. For hand lay up applications, the viscosity of the solution is not very critical. However, if the composition has to be used on a mechanical coating unit, the viscosity of the formulation becomes critical. If the right viscosity is not maintained the coating thickness would vary and the non-uniformity would pose problems in processing.
The viscosity of the polymer solution as obtained from the reactor is not sufficient for mechanical coating applications and there is a need to improve the viscosity by suitable additives so that the viscosity can be adjusted to suit the mechanical device of choice.
The known compositions available suffers from the disadvantage that the viscosity of the solution cannot be changed to suit the mechanical device of choice for getting a uniform film. Changes in the viscosity of the photo-curable composition should be made in such a way the resulting polymer can be readily used for photoresist formulations. The primary requirements for such applications are -
1. The polymer should contain carboxylic acid groups such that the polymer after exposure to UV source should be aqueous soluble.

2. The polymer should have sufficient mechanical strength so that
during the processing stage, the film remains in tact.
3. The polymer should contain aromatic groups so that quantum
efficiency during the photochemical reaction step is possible.
4. The glass temperature of the polymer should be close to ambient
temperature.
These characteristics should not be disturbed while improving the viscosity.
The main object of the present invention is therefore to provide a process for the preparation of photo-curable compositions with improved viscosity.
Another object of the present invention is to provide a process for the preparation of photo-curable compositions with improved viscosity so that die glass transition temperature and mechanical strength are not altered.
Yet another object of the present invention is to provide a process for the preparation of photo-curable compositions with improved viscosity that does not disturb the photochemical reaction to give image of choice after developing.

Accordingly, the present invention provides an improved process for preparation of photo-curable composition of modified changeable viscosity for dry resist application comprising mixing in an inert atmosphere a photocurable polymer solution as claimed in the copending application 813/DEL/2000 with an aliphatic amine such as hexyl amine, octyl amine, dodecyl amine at concentration of 1 to 10% for a period ranging from 10 to 30 minutes at a temperature of 25° to 30°C and collecting the resultant product in the form of solution.
In one of the embodiments of the invention, the inert gas used may be nitrogen, argon.
In another embodiment the aliphatic amine used may be haxylamine, octyl amine, dodacyl amine and the concentration used may be 0.1 to 0.05%.
In still another embodiment of the present invention, the photo-curable formulation used may be prepared by mixing in an yellow light atmosphere, a photo-curable polymer solution with an organic dye, a sensitizer, photo-initiator, crosslinking monomar, solvent, for a period ranging from 20 to 60 minutes, at a temperature in the range of 25 to 35°C, till uniform consistency is achieved and collecting the product in the form of a solution. The process of the present invention is described with reference to following examples, which are illustrative only and should not be construed to limit the scope of this invention in any manner.
EXAMPLE-1
In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.15 gms of octyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 15 minutes of reaction, was collected in the form of a solution. The yield obtained was 100 ml.

EXAMPLE-2
In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.38 gins of octyl amine and solution was maintained isothermally at 35°C for 10 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 10 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml.
Example 3
In an inert atmosphere of argon, to 150 ml of polymer solution was added 2.25 gms of octyl amine and solution was maintained isothermally at 30°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 150ml.
EXAMPLE - 4 In an inert atmosphere of nitrogen, to 200 ml of polymer solutic n was added 1.5 gms
of octyl amine and solution was maintained isothermally at 25°C for 30 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 30 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml.

Example 5
In an inert atmosphere of argon, to 100 ml of polymer solution was added 0.25 gms of dodecyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 10 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml.
EXAMPLE - 6
In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.55 gms
of dodecyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 15 minutes of reaction, was collected in the form of a solution. The yield obtained was 100 ml.
EXAMPLE - 7 In an inert atmosphere of nitrogen, to 150 ml of polymer solution was added 1.65 gms
of octyl amine and solution was maintained isothermally at 30°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 150ml.
EXAMPLE-8
In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.15 gms
of octyl amine and solution was maintained isothermally at 25°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 10 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml.

EXAMPLE - 9
In an inert atmosphere of nitrogen, to 200 ml of polymer solution was added 4.5 gms of dodecyl amine and solution was maintained isothermally at 25°C for 30 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 30 minutes of reaction, was collected in the form of a solution. The yield obtained was 200 ml.
EXAMPLE - 10
In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.15 gms of hexyl amine and solution was maintained isothermally at 25°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 100 ml.
EXAMPLE-11
In an inert atmosphere of nitrogen, to 100 ml of polymer solution was added 0.35 gms of hexyl amine and solution was maintained isothermally at 30°C for 15 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 15 minutes of reaction, was collected in the form of a solution. The yield obtained was 100ml.
EXAMPLE - 12
In an inert atmosphere of nitrogen, to 200 ml of polymer solution was added 2.4 gms of hexyl amine and solution was maintained isothermally at 35°C for 30 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 30

minutes of reaction, was collected in the form of a solution. The yield obtained was 202 ml.
EXAMPLE - 13
In an inert atmosphere of nitrogen, to 150 ml of polymer solution was added 1.15 gms of hexyl amine and solution was maintained isothermally at 35°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 150ml.
EXAMPLE - 14
IP iii inert atmosphere of nitrogen, to 200 ml of polymer solusion was added 2.15 gms of dodecyl amine and solution was maintained isothermally at 35°C for 20 minutes. The stirring rate was maintained at 300 rpm. The product remaining at the end of 20 minutes of reaction, was collected in the form of a solution. The yield obtained was 202 ml.
Advantages of the present invention:
1. The photo-curable compositions with improved viscosity prepared by the process
of this invention are aqueous developable.
2. The photo-curable compositions with improved viscosity obtained by the process
of this invention can be directly used for the coating of film onto copper clad
laminate in PCB industriesof dryresists.
3. The process of this invention is amenable for scale up operation.

WE CLAIM
1. An improved process for preparation of photo-curable composition of modified
changeable viscosity for dry resist application comprising mixing in an inert
atmosphere a photocurable polymer solution as claimed in the copending
application 813/DEL/2000 with an aliphatic amine such as hexyl amine, octyl
amine, dodecyl amine at concentration of 1 to 10% for a period ranging from 10
to 30 minutes at a temperature of 25° to 30°C and collecting the resultant product
in the form of solution.
2. A process as claimed in claim 1, wherein, the inert gas used may be nitrogen or
argoa
3. A process for the preparation of photo-curable compositions with modified
viscosity for dry resist application as substantially described with reference to the
example.

Documents:

815-del-2000-abstract.pdf

815-del-2000-claims.pdf

815-del-2000-correspondence-others.pdf

815-del-2000-correspondence-po.pdf

815-del-2000-description (complete).pdf

815-del-2000-form-1.pdf

815-del-2000-form-19.pdf

815-del-2000-form-2.pdf

815-del-2000-form-26.pdf

815-del-2000-form-4.pdf

815-del-2000-petition-138.pdf

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Patent Number

216749

Indian Patent Application Number

815/DEL/2000

PG Journal Number

13/2008

Publication Date

31-Mar-2008

Grant Date

19-Mar-2008

Date of Filing

07-Sep-2000

Name of Patentee

THE SECRETORY, MINISTRY OF INFORMATION TECHNOLOGY (FORMERLY DOE) GOVT. OF INDIA

Applicant Address

ELECTRONICS NIKETAN, 6 CGO COMPLEX LODHI ROAD, NEW DELHI - 110003, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	VARSHA BHIKOBA GHADGE	SCIENTIST IPM DIVISION, COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH, RAFI MARG, NEW DELHI- 110001, INIDA
2	CHELANATTU KHIZHAKKE	SCIENTIST IPM DIVISION, COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH, RAFI MARG, NEW DELHI- 110001, INIDA
3	MADATH RAMAN RAJAN	SCIENTIST IPM DIVISION, COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH, RAFI MARG, NEW DELHI- 110001, INIDA
4	SURENDRA PONRATHANAM	SCIENTIST IPM DIVISION, COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH, RAFI MARG, NEW DELHI- 110001, INIDA

PCT International Classification Number

G03C 5/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA