阅读说明：本技术 一种碱可溶性共聚物及其制备方法 (Alkali-soluble copolymer and preparation method thereof ) 是由 袁丽 朱高华 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种碱可溶性共聚物及其制备方法,所述的碱可溶性共聚物是由含有极性较大的酰胺基、脲基或者磺酰胺基并且含有柔性较好的脂肪烃环结构的第一单体与第二单体、第三单体及第四单体发生聚合反应制得的。所述碱可溶性共聚物酸值为120～250 mg KOH/g,重均分子量为30000～150000,分子量分布为1.3～2.5,聚合转化率≥97%。本发明所述的碱可溶性共聚物兼具良好的机械性能和柔韧性,所述的碱性可溶性共聚物可应用于高精密印刷电路板、引线框架、太阳能电池、导体封装等电子材料行业；具有良好的应用前景。(The invention discloses an alkali-soluble copolymer and a preparation method thereof, wherein the alkali-soluble copolymer is prepared by carrying out polymerization reaction on a first monomer, a second monomer, a third monomer and a fourth monomer, wherein the first monomer contains amide groups, carbamido groups or sulfonamide groups with larger polarity and contains an aliphatic hydrocarbon ring structure with better flexibility. The acid value of the alkali-soluble copolymer is 120-250 mg KOH/g, the weight average molecular weight is 30000-150000, the molecular weight distribution is 1.3-2.5, and the polymerization conversion rate is more than or equal to 97%. The alkali soluble copolymer has good mechanical property and flexibility, and can be applied to the electronic material industries of high-precision printed circuit boards, lead frames, solar cells, conductor packaging and the like; has good application prospect.)

1. An alkali-soluble copolymer characterized by: the alkali-soluble copolymer is prepared by the polymerization reaction of a first monomer, a second monomer, a third monomer and a fourth monomer; the structural general formula (I) of the first monomer is shown as follows,(I), wherein R, R is a hydrogen atom or an alkyl group having C1-C5; n is an integer of 0 to 6; cyclic is an alicyclic ring;

the structural general formula (II) of the second monomer is shown as follows,

(II) in the formula, R₄Is a hydrogen atom or a methyl group;

the structural general formula (III) of the third monomer is shown as the following formula,

(III) in the formula, R₅Is a hydrogen atom or a methyl group, R₆Is C1-C18 alkyl or benzyl;

the structural general formula of the fourth monomer is (A)) As shown in the following formula,

(IV) in the formula, R₇Is a hydrogen atom or a methyl group, R₈Is C1-C3 alkyl, C1-C3 alkoxy, amino or halogen atom, and the number of substituents on the benzene ring is 0-5.

2. An alkali-soluble copolymer according to claim 1, wherein: the structure of the fat ring is an alicyclic hydrocarbon group or an aliphatic heterocyclic group, and the chemical structure of the fat ring comprises

In the formula R₁~R₃The aliphatic ring is C1-C8 alkyl, and the structure of the aliphatic ring further comprises an alkyl substituent or a heteroatom.

3. An alkali-soluble copolymer according to claim 2, wherein: the heteroatom comprises one or more of oxygen, sulfur or nitrogen atoms.

4. An alkali-soluble copolymer according to claim 1, wherein: the nitrogen atom connected with the fat ring in the amido, carbamido or sulfamide group in the structural formula A, B, C of the general formula (I) is on or adjacent to the fat ring.

5. An alkali-soluble copolymer according to claim 1, wherein: the acid value of the alkali-soluble copolymer is 120-250 mg KOH/g, the weight average molecular weight is 30000-150000, the molecular weight distribution is 1.3-2.5, and the polymerization conversion rate is more than or equal to 97%.

6. An alkali-soluble copolymer according to claim 1, wherein: the initiator is azobisisobutyronitrile.

7. An alkali-soluble copolymer according to claim 1, wherein: in the polymerization reaction, the raw materials comprise, by weight, 10-40 parts of a first monomer, 15-35 parts of a second monomer, 20-35 parts of a third monomer and 0-25 parts of a fourth monomer.

8. The process for producing an alkali-soluble copolymer according to claim 1, comprising the steps of:

weighing 100g of the first monomer, 100g of the second monomer, 100g of the third monomer and 100g of the fourth monomer according to the proportion, uniformly mixing, adding 0.3-0.8 g of an initiator, adding 90-95 g of butanone and 12-15 g of ethanol, and stirring until the mixture is dissolved to obtain a mixed solution;

adding 35-40% of the obtained mixed solution into a three-necked flask provided with a nitrogen protection device and a condensation reflux device, heating to 75-80 ℃ in an oil bath, reacting for 1-1.2 h under a stirring condition, slowly dropwise adding the rest of the mixed solution into the reaction system, and completing dropwise adding within 2.5-3 h;

after the dropwise addition is finished, continuing the heat preservation reaction for 4-4.5 h, raising the temperature to 90-95 ℃ for continuing the reaction, supplementing 20-25 g of butanone solution in which 0.1-0.3 g of initiator is dissolved twice in the reaction system during the reaction period, wherein the interval time of the two times is 1-1.1 h, after the supplementing is finished, preserving the heat and stirring for 4-4.2 h, finishing the reaction, and thus obtaining the alkali-soluble copolymer.

Technical Field

The invention relates to the technical field of photoresist, in particular to an alkali soluble copolymer and a preparation method thereof.

Background

In the manufacture of printed circuit boards, copolymers of acrylic acid and acrylic esters are generally used as the base material of the photosensitive dry film. However, the acrylic acid-acrylate copolymer system is soft, has insufficient mechanical strength, has insufficient adhesion to substrates such as copper clad laminate, and cannot meet the manufacturing requirements of high-precision packaging substrates. In order to ensure high resolution and high adhesion of the photoresist, a method of adding benzyl (meth) acrylate, styrene, and styrene derivatives having better adhesion and rigidity as copolymerization components to the alkali-soluble resin of the photosensitive resin composition is generally used. However, the introduction of styrene also brings obvious disadvantages: on one hand, the obtained film material is hard and brittle, and the adhesion force with the copper-clad plate base material is not enough; on the other hand, the compatibility of the molecular structure of the copolymer and the main structure of the acrylate is poor, self-polymerization is easy to occur in the copolymerization process, and some self-polymerization residues are generated. Due to the defects, the copolymerization system of acrylic acid-acrylate-styrene and derivatives thereof can not meet the use requirements of high-density connection in the production of electronic materials such as modern printed circuit boards, conductor packaging and the like.

Patent CN104730863B discloses a preparation method and application of amino or hydroxyl modified acrylic acid-acrylate-styrene and its derivative copolymer, through which the adhesion between the polymer and the substrate such as copper clad plate is improved, but the modification does not relate to the balance of the mechanical strength and flexibility of the material.

In summary, in order to meet the manufacturing requirements of high-precision sealed substrates, a polymer which has high adhesion on substrates such as copper clad laminates and the like and can give consideration to mechanical strength and flexibility is prepared as a substrate of photoresists such as photosensitive dry films and the like, and the prepared polymer is a difficult problem to be solved urgently in the electronic material industries such as printed circuit boards, lead frames, solar cells, conductor packages and the like.

Disclosure of Invention

The invention aims to solve the problems and provides an alkali soluble copolymer which has good mechanical strength and flexibility and can be used in the field of photoresists such as dry film resists and photosensitive covering films.

In order to achieve the purpose, the technical method adopted by the invention is as follows:

an alkali-soluble copolymer is prepared by the polymerization reaction of a first monomer, a second monomer, a third monomer and a fourth monomer; the structural general formula (I) of the first monomer is shown as follows,

(I), wherein R, R is a hydrogen atom or an alkyl group having C1-C5; n is an integer of 0 to 6; cyclic is an alicyclic ring;

the structural general formula (II) of the second monomer is shown as follows,

(II) in the formula, R₄Is a hydrogen atom or a methyl group;

the general structural formula of the (methyl) acrylic ester (III) is shown as the formula (III)

(III) in the formula, R₅Is a hydrogen atom or a methyl group, R₆Is C1-C18 alkyl or benzyl;

the structural general formula (IV) of the fourth monomer is shown as the following formula,

(IV) in the formula, R₇Is a hydrogen atom or a methyl group, R₈Is C1-C3 alkyl, C1-C3 alkoxy, amino or halogen atom, and the number of substituents on the benzene ring is 0-5.

Preferably, the structure of the alicyclic ring is alicyclic hydrocarbon group or alicyclic heterocyclic group, and the chemical structure of the alicyclic hydrocarbon group or the alicyclic heterocyclic group comprises

Wherein R is₁~R₃The aliphatic ring is C1-C8 alkyl, and the structure of the aliphatic ring further comprises an alkyl substituent or a heteroatom.

The first monomer is vinyl polymerizable monomer (I) containing amide group, carbamido group or sulfonamide group with larger polarity and containing aliphatic hydrocarbon ring structure with better flexibility, the second monomer is (methyl) acrylic acid (II), the third monomer is (methyl) acrylate (III), and the fourth monomer is styrene and derivative (IV) thereof.

Preferably, the heteroatoms include one or more of oxygen, sulfur or nitrogen atoms.

Preferably, the nitrogen atom of the amide group, the ureido group or the sulfonamide group in the formula A, B, C of the general structural formula (I) which is connected with the aliphatic ring is on or adjacent to the aliphatic ring.

Preferably, the acid value of the alkali-soluble copolymer is 120-250 mg KOH/g, the weight average molecular weight is 30000-150000, the molecular weight distribution is 1.3-2.5, and the polymerization conversion rate is more than or equal to 97%.

The acid value of the alkali-soluble copolymer is 120-250 mg KOH/g, the acidity meets the use requirement, and the alkali-soluble copolymer is proved to be moderate in rigidity and flexibility and has good mechanical property and flexibility. If the acid value is more than 250 mg KOH/g, the photoresist has too strong solubility in alkali liquor, the photoresist is over developed, the analysis capability is influenced, and if the acid value is more than 250 mg KOH/g, the glass transition temperature (Tg) of the obtained alkali-soluble copolymer can be obviously increased, so that the photoresist taking the alkali-soluble copolymer as a base material is hardened and becomes brittle, and the flexibility is obviously reduced; too low an acid number may affect the solubility of the alkali-soluble polymer in the alkaline solution, which may affect the development rate of the photoresist, and thus the resolving power of the photoresist.

Preferably, the initiator is azobisisobutyronitrile.

Preferably, in the polymerization reaction, the raw materials comprise, by weight, 10-40 parts of a first monomer, 25-30 parts of a second monomer, 20-35 parts of a third monomer and 0-25 parts of a fourth monomer.

It is another object of the present invention to provide a method for preparing the alkali-soluble copolymer, comprising the steps of:

weighing 100g of the first monomer, 100g of the second monomer, 100g of the third monomer and 100g of the fourth monomer according to the proportion, uniformly mixing, adding 0.3-0.8 g of an initiator, adding 90-95 g of butanone and 12-15 g of ethanol, and stirring until the mixture is dissolved to obtain a mixed solution;

adding 35-40% of the obtained mixed solution into a three-necked flask provided with a nitrogen protection device and a condensation reflux device, heating to 75-80 ℃ in an oil bath, reacting for 1-1.2 h under a stirring condition, slowly dropwise adding the rest of the mixed solution into the reaction system, and completing dropwise adding within 2.5-3 h;

after the dropwise addition is finished, continuing the heat preservation reaction for 4-4.5 h, raising the temperature to 90-95 ℃ for continuing the reaction, supplementing 20-25 g of butanone solution in which 0.1-0.3 g of initiator is dissolved twice in the reaction system during the reaction period, wherein the interval time of the two times is 1-1.1 h, after the supplementing is finished, preserving the heat and stirring for 4-4.2 h, finishing the reaction, and thus obtaining the alkali-soluble copolymer.

The invention has the following beneficial effects:

the alkali-soluble copolymer is obtained by simultaneously introducing strong polar groups such as amido, carbamido or sulfonamide and the like and aliphatic hydrocarbon ring structural groups with better flexibility into an acrylic acid-acrylate-styrene copolymer; the addition of the amido, carbamido or sulfonamide improves the mechanical strength of the alkali-soluble copolymer, and when the alkali-soluble copolymer is used as a base material of a photoresist, the adhesion between the photoresist and a copper base material can be increased, and the developability of the photoresist can be improved; the introduction of the aliphatic hydrocarbon ring structure makes the alkali-soluble copolymer flexible. The alkali soluble copolymer can be applied to the electronic material industries of high-precision printed circuit boards, lead frames, solar cells, conductor packaging and the like; has good application prospect.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Unless defined otherwise, technical or scientific terms used in the present disclosure shall have the ordinary meaning as understood by those skilled in the art to which the invention pertains.

The molecular weight of the alkali-soluble copolymer is measured by adopting a GPC method, wherein the GPC method is gel permeation chromatography, is liquid chromatography, and is a method for separating polymers according to different hydrodynamic volumes by using a polymer solution through a column filled with microporous gel.

Example 1

An alkali soluble copolymer was prepared as follows:

a preparation of a first monomer corresponding to formula A in formula (1), i.e., an amido-containing vinyl polymerizable monomer (I)

Adding dichloromethane (500 ml), cyclohexylamine 99.2 g (1 mol) and triethylamine 1.05-3.0 equivalents into a three-neck flask connected with a thermometer, a stirring device, a dropping funnel, a nitrogen protection device and an ice bath cooling device, replacing nitrogen, cooling in an ice bath, slowly dropping methacryloyl chloride 1.05-1.5 equivalents when the temperature of a reaction system is reduced to below 5 ℃, keeping the dropping process for 0.5-1 hour, keeping the temperature at 2-5 ℃, continuing to react in the ice bath for 1-3 hours after the dropping is finished, removing the ice bath, continuing to react at room temperature for 0.5-5 hours, and finishing the reaction. After the reaction is finished, removing hydrochloride of triethylamine generated in the reaction process through vacuum filtration, adding 1M dilute hydrochloric acid (200 ml) into filtrate, stirring for 15 minutes, extracting for 2 times by using dichloromethane (200 ml), washing obtained combined organic phases by using saturated saline solution, drying by using anhydrous sodium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and dispersing the crude product in petroleum ether: stirring for 1 hour in a mixed solvent (300 ml) of ethyl acetate (10: 1), filtering the obtained solid under reduced pressure, and drying to obtain the amido-containing vinyl polymerizable monomer (I): n-cyclohexyl methacrylamide.

B preparation of alkali-soluble copolymers

Prepared by free radical solution polymerization, comprising the following steps:

weighing raw materials of a first monomer, a second monomer, a third monomer and a fourth monomer according to the proportion, wherein the raw materials and the proportion of the raw materials in the embodiment of the invention are as follows: n-cyclohexylmethacrylamide/styrene/methacrylic acid/methyl methacrylate = 30/25/25/20, totaling 100g, mixed well, initiator 0.6 g AIBN added, butanone 95g and ethanol 15g added, dissolved with stirring, and the like to a mixed solution. Adding about 35% of mixed solution by mass fraction into a three-neck flask provided with a nitrogen protection and condensation reflux device through a peristaltic pump, heating to 78 ℃ through oil bath, stirring for reacting for 1h, slowly dropwise adding the rest mixed solution, and finishing the adding within 3 h. And after continuing the heat preservation reaction for 4 hours, heating to 90 ℃, supplementing 20g of butanone solution dissolved with 0.1-0.3 g of initiator twice at an interval of 1 hour, preserving heat and stirring for 2 hours after finishing the dropwise addition, and finishing the reaction. The obtained alkali-soluble copolymer had a weight-average molecular weight of 70000 as measured by GPC, a molecular weight distribution coefficient of 1.8, a polymerization conversion of 98% and a solid content of 41%.

Example 2

An alkali soluble copolymer was prepared as follows:

the first monomer corresponding to formula A in formula (1) used in the examples of the present invention, i.e., the amide group-containing vinyl polymerizable monomer (I), was 4-acryloylmorpholine, which was obtained commercially as it is. Weighing raw materials of a first monomer, a second monomer, a third monomer and a fourth monomer according to the proportion, wherein the raw materials and the proportion of the raw materials in the embodiment of the invention are as follows: 4-acryloylmorpholine/styrene/methacrylic acid/methyl methacrylate = 20/25/25/30, totaling 100g, and uniformly mixing, adding 0.5 g of initiator AIBN (azobisisobutyronitrile), adding 95g of butanone and 15g of ethanol, and stirring to dissolve to obtain a mixed solution. Adding about 35% of mixed solution by mass fraction into a three-neck flask provided with a nitrogen protection device and a condensation reflux device through a peristaltic pump, heating to 75-80 ℃ through oil bath, stirring for reaction for 1h, slowly dropwise adding the rest mixed solution, and finishing the adding within 3 h. And after continuing the heat preservation reaction for 4 hours, heating to 90 ℃, supplementing 20g of butanone solution dissolved with 0.1-0.3 g of initiator twice at an interval of 1 hour, preserving heat and stirring for 2 hours after finishing the dropwise addition, and finishing the reaction. The obtained alkali-soluble copolymer had a weight-average molecular weight of 81000 as measured by GPC, a molecular weight distribution coefficient of 1.9, a polymerization conversion of 98%, and a solid content of 40%.

The specific synthetic route is as follows:

wherein, the aliphatic ring connected with nitrogen of the amide group is an aliphatic ring type hydrocarbon group which can have substituent groups or a heterocyclic group which can have substituent groups, the ring can optionally contain alkyl substituent groups or heteroatoms such as oxygen, sulfur, nitrogen and the like, and the nitrogen atom connected with the aliphatic ring in the amide group can be on the ring or adjacent to the aliphatic ring; in the structural formula of the copolymer component acrylate, R is selected from alkyl or benzyl of C1-C18 which can have substituent groups.

The synthesis method of other aliphatic cyclic amide modified alkali soluble copolymers is similar to that of example 1 or 2, and thus the details are not repeated here.

Example 3

An alkali soluble copolymer was prepared as follows:

preparation of a first monomer corresponding to formula B in formula (1), i.e. a ureido-containing vinyl-polymerizable monomer (I)

Adding 1-amantadine (151 g, 1 mol) and tetrahydrofuran (500 ml) into a three-neck flask provided with a thermometer, a stirring device, a dropping funnel, a nitrogen protection device and an ice bath cooling device, adding 1.2-1.5 equivalents of triethylamine, replacing with nitrogen, cooling in an ice bath, slowly dropwise adding 0.95-1.0 equivalent of allyl isocyanate when the temperature of a reaction system is reduced to be lower than 5 ℃, keeping the dropwise adding process for 1 hour, keeping the temperature at 2-5 ℃, continuously carrying out ice bath reaction for 1 hour after the dropwise adding is finished, removing the ice bath, continuously carrying out room temperature reaction for 1 hour, and finishing the reaction. Concentrating under reduced pressure to remove tetrahydrofuran, adding water (500 ml), extracting the water phase with ethyl acetate for 2 times, combining the organic phases, washing with 1M dilute hydrochloric acid and saturated saline solution in sequence, drying with anhydrous sodium sulfate, filtering, concentrating under reduced pressure to obtain a crude product, and dispersing the crude product in petroleum ether: stirring the mixture (300 ml) of ethyl acetate (20: 1) for 1 hour, filtering the mixture under reduced pressure to obtain a solid, and drying the solid to obtain the purified 1-propenyl-3-adamantyl urea.

B preparation of alkali-soluble copolymers

Prepared by free radical solution polymerization, comprising the following steps:

weighing raw materials of a first monomer, a second monomer, a third monomer and a fourth monomer according to the proportion, wherein the raw materials and the proportion of the raw materials in the embodiment of the invention are as follows: the preparation method comprises the following steps of (1) -propenyl-3-adamantyl urea/styrene/methacrylic acid/methyl methacrylate = 15/25/25/35, wherein the total amount of 100g is obtained, uniformly mixing, adding 0.6-0.8 g of initiator AIBN, adding 95g of butanone and 15g of ethanol, and stirring and dissolving to obtain a mixed solution. Adding about 35% of mixed solution by mass fraction into a three-neck flask provided with a nitrogen protection device and a condensation reflux device through a peristaltic pump, heating to 75-80 ℃ through oil bath, stirring for reaction for 1h, slowly dropwise adding the rest mixed solution, and finishing the adding within 3 h. And after continuing the heat preservation reaction for 4 hours, heating to 90 ℃, supplementing 20g of butanone solution dissolved with 0.2-0.3 g of initiator twice at an interval of 1 hour, preserving heat and stirring for 2 hours after finishing the dropwise addition, and finishing the reaction. The obtained alkali-soluble copolymer had a weight-average molecular weight of 49000 as measured by GPC, a molecular weight distribution coefficient of 2.0, a polymerization conversion of 97%, and a solid content of 40%.

The specific synthetic route is as follows:

wherein, the aliphatic ring connected with nitrogen in the carbamido group is aliphatic ring type hydrocarbyl which can have substituent or heterocyclic group which can have substituent, the ring can optionally contain alkyl substituent or hetero atom such as oxygen, sulfur, nitrogen and the like, and the nitrogen atom connected with the aliphatic ring in the amido group can be on the ring or adjacent to the aliphatic ring; in the structural formula of the copolymer component acrylate, R is selected from alkyl or benzyl of C1-C18 which can have substituent groups.

The synthesis of other similar aliphatic cyclic amide modified alkali soluble copolymers is similar to that of example 3 and is not repeated here.

Example 4

An alkali soluble copolymer was prepared as follows:

preparation of a first monomer corresponding to formula C in formula (1), i.e., a sulfonamide group-containing vinyl polymerizable monomer (I)

Adding 1-amantadine (151 g, 1 mol) and dichloromethane (500 ml) into a three-neck flask provided with a thermometer, a stirring device, a dropping funnel, a nitrogen protection device and an ice bath cooling device, then adding 1.1-2.0 equivalent of triethylamine, replacing with nitrogen, cooling in an ice bath, slowly dropwise adding 0.9-0.95 equivalent of 2-chloroethanesulfonyl chloride when the temperature of a reaction system is reduced to be below 5 ℃, removing the ice bath after dropwise adding, and continuously reacting for 5 hours at room temperature. After the reaction, the reaction solution was poured into water (100 ml) to quench, the resulting solution was extracted 3 times with dichloromethane, the combined organic phases were washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to obtain a crude product, which was dispersed in petroleum ether: stirring the mixture (300 ml) of ethyl acetate (10: 1) for 1 hour, filtering the mixture under reduced pressure to obtain a solid, and drying the solid to obtain the purified N-adamantyl vinyl sulfonamide.

B is prepared by free radical solution polymerization, comprising the following steps:

weighing raw materials of a first monomer, a second monomer, a third monomer and a fourth monomer according to the proportion, wherein the raw materials and the proportion of the raw materials in the embodiment of the invention are as follows: the preparation method comprises the following steps of (1) uniformly mixing 100g of N-adamantyl vinylsulfonamide/methacrylic acid/benzyl acrylate = 50/30/20 in total, adding 0.6-0.8 g of AIBN serving as an initiator, adding 95g of butanone and 15g of ethanol, and stirring for dissolving to obtain a mixed solution. Adding about 35% of mixed solution by mass fraction into a three-neck flask provided with a nitrogen protection device and a condensation reflux device through a peristaltic pump, heating to 75-80 ℃ through oil bath, stirring for reaction for 1h, slowly dropwise adding the rest mixed solution, and finishing the adding within 3 h. And after continuing the heat preservation reaction for 6 hours, heating to 90 ℃, supplementing 20g of butanone solution dissolved with 0.1-0.3 g of initiator twice at an interval of 1 hour, preserving heat and stirring for 4 hours after finishing the dropwise addition, and finishing the reaction. An alkali-soluble copolymer was obtained, which had a weight-average molecular weight of 48000 as measured by GPC, a molecular weight distribution coefficient of 2.1, a polymerization conversion of 97%, and a solid content of 38%.

The specific synthetic route of the embodiment of the invention is shown as follows:

the above-described preferred embodiments of the present invention are not intended to limit the present invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the claims of the present invention.