CN114149530B

CN114149530B - Alkali-soluble polymer for preparing LDI dry film and preparation method thereof

Info

Publication number: CN114149530B
Application number: CN202111117656.8A
Authority: CN
Inventors: 邹应全; 张强; 陈京; 包春阳; 王义军; 刘明珂; 赵凤娇
Original assignee: Sichuan Lekai New Material Co ltd; Baoding Lucky Innovative Materials Co ltd
Current assignee: Aerospace Intelligent Manufacturing Technology Co ltd; Sichuan Lekai New Material Co ltd
Priority date: 2021-09-23
Filing date: 2021-09-23
Publication date: 2023-07-21
Anticipated expiration: 2041-09-23
Also published as: CN114149530A

Abstract

The invention relates to an alkali-soluble polymer for preparing an LDI dry film and a preparation method thereof. The alkali-soluble polymer side chains according to the invention have oxetane groups; and the polymerized units containing oxetane groups account for 1-65% by mass of the alkali-soluble polymer. The alkali-soluble polymer is prepared by adopting a free radical polymerization method. The alkali-soluble polymer is used for preparing the LDI dry film, and the LDI dry film prepared by matching the alkali-soluble polymer and the cationic initiator is directly exposed by laser, so that the LDI dry film has good sensitivity, resolution, adhesiveness, cover porosity and resist shape compared with the LDI dry film in the prior art.

Description

Alkali-soluble polymer for preparing LDI dry film and preparation method thereof

Technical Field

The invention relates to the field of PCBs (printed circuit boards), in particular to an alkali-soluble polymer for preparing an LDI (Low Density polyethylene) dry film and a preparation method thereof.

Background

PCB, printed circuit board, is an abbreviation for Printed circuit Board; the LDI dry film, namely a laser direct imaging dry film, is an abbreviation of laser direct imaging and is an important material for a laser direct imaging process in the PCB field.

According to the market depth investigation and investment prospect prediction analysis report of the photosensitive dry film industry of 2019-2024, the PCB industry is rapidly developed along with technological innovation, the demand of the PCB dry film in China is exponentially increased year by year, and various enterprises related to the PCB are continuously appeared along with the expansion of market scale.

The requirement scale of the 2014 Chinese photosensitive dry film industry is 30.84 hundred million yuan; the expert shows that the demand scale of the photosensitive dry film industry in China is expected to be increased to 100.95 hundred million yuan in 2024.

With the continuous progress of technology, LDI dry films have been developed under the drive of the miniaturization of electronic devices and the high densification of circuits.

However, when the LDI dry film in the prior art is used for laser direct imaging, the problems of lower sensitivity, resolution, adhesiveness and cover porosity and poorer resist shape exist.

Based on this, there is a need to provide an LDI dry film that simultaneously improves the above properties.

Among them, the alkali-soluble polymer is an important intermediate for preparing the LDI dry film, and the inventors have found that the main chain and side chain of the existing alkali-soluble polymer do not contain a group that can undergo cationic polymerization, and that the alkali-soluble polymer does not undergo a crosslinking reaction in the process of laser exposure after it constitutes the LDI dry film, which is one of the reasons why the above properties of the LDI dry film cannot be improved.

Accordingly, it is desirable to provide an alkali soluble polymer to enhance the above properties of the LDI dry film.

Disclosure of Invention

The invention provides an alkali-soluble polymer for preparing an LDI dry film and a preparation method thereof. After the alkali-soluble polymer is prepared into the LDI dry film, in the laser direct exposure process, the alkali-soluble polymer is matched with a cationic initiator to generate cationic polymerization reaction between the inside of an alkali-soluble polymer chain and the alkali-soluble polymer chain to form a crosslinked network, so that the hardness and the cohesiveness of the LDI dry film are improved, and the technical problems of low sensitivity, resolution, adhesiveness and cover porosity of the LDI dry film and poor shape of a resist are solved.

According to an aspect of the present invention, there is provided an alkali-soluble polymer for preparing an LDI dry film, the side chain of the alkali-soluble polymer having oxetanyl groups; and the polymerized units containing oxetane groups account for 1 to 65 percent of the alkali-soluble polymer by mass percent.

According to one embodiment of the alkali-soluble polymer of the present invention, the polymeric monomers constituting the polymeric units containing oxetane groups are represented by formula I and/or formula II:

preferably, n is a natural number from 1 to 3.

According to one embodiment of the alkali-soluble polymer of the present invention, the alkali-soluble polymer further includes polyacrylic acid units therein;

preferably, the polymeric monomer constituting the polyacrylic unit is selected from at least one of the following: acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, and maleic half esters.

According to one embodiment of the alkali-soluble polymer of the present invention, the alkali-soluble polymer further comprises a polyalkylacrylate unit;

preferably, the polymeric monomer constituting the polyalkylacrylate unit is selected from at least one of the following: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate and butyl methacrylate.

According to one embodiment of the alkali-soluble polymer of the present invention, the alkali-soluble polymer further includes a benzene ring-containing polymerized unit therein;

preferably, the polymeric monomer constituting the benzene ring-containing polymeric unit is selected from at least one of the following: benzyl acrylate and its derivatives, benzyl methacrylate and its derivatives, styrene and its derivatives.

According to one embodiment of the alkali-soluble polymer of the present invention, the alkali-soluble polymer has a weight average molecular weight of 10000 to 200000Da;

Preferably, the glass transition temperature of the alkali-soluble polymer is 100 to 150 ℃;

preferably, the acid value of the alkali-soluble polymer is 100 to 250mgKOH/g;

preferably, the alkali-soluble polymer has a dispersity of 1.0 to 8.0.

According to one embodiment of the alkali-soluble polymer of the present invention, the polymerization unit constituting the alkali-soluble polymer includes: a polymethacrylic acid unit, a polymethylmethacrylate unit and a polymethylmethacrylate (3-ethyloxetan-3-yl) methyl ester unit;

preferably, the polymethacrylic acid unit accounts for 5-50% by mass based on the total mass of the alkali-soluble polymer; the poly (benzyl methacrylate) unit accounts for 1-50%, the poly (methyl methacrylate) unit accounts for 1-80%, and the poly (3-ethyloxetan-3-yl) methyl methacrylate accounts for 1-65%.

According to another aspect of the present invention, there is provided a method for preparing an alkali-soluble polymer for LDI dry film, dissolving a polymerization monomer, a radical initiator and a chain transfer agent in a solvent, obtaining an alkali-soluble polymer solution through radical polymerization; wherein, the liquid crystal display device comprises a liquid crystal display device,

the polymerized monomer comprises polymerized monomers containing oxetanyl, and the polymerized monomers account for 1 to 65 percent by mass percent;

Preferably, the oxetanyl group-containing polymeric monomer is of formula I and/or formula II:

preferably, n is a natural number from 1 to 3;

according to one embodiment of the preparation method of the present invention, the alkali-soluble polymerized monomer further includes an acrylic monomer;

preferably, the acrylic monomer is selected from at least one of the following: acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, and maleic half esters.

According to one embodiment of the preparation process of the present invention, the chain transfer agent is selected from at least one of the following: dodecyl mercaptan, thioglycollic acid, isopropyl alcohol and sodium hypophosphite;

preferably, the chain transfer agent is used in an amount of 0.1 to 5% by mass of the polymerized monomer.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

the LDI dry film is prepared by adopting the alkali-soluble polymer, and the alkali-soluble polymer and the cationic initiator are matched for use.

Because the side chain of the alkali-soluble polymer is provided with the oxetane group, when the laser is directly exposed, on one hand, the oxetane group of the side chain of the alkali-soluble polymer can be opened under the initiation of a cationic initiator, and a cationic crosslinking reaction occurs in the alkali-soluble polymer chain and between the polymer chains; on the other hand, compared with free radical polymerization, cationic polymerization has no problems such as oxygen inhibition, and the like, and LDI dry film shrinkage rate is small.

The photosensitivity of the LDI dry film is improved based on the reaction of cationic polymerization occurring inside the alkali-soluble polymer.

Based on the two aspects, the hardness and the bonding strength of the LDI dry film exposure area are improved, and the alkali resistance of the exposure crosslinking area is further improved, so that the photosensitivity, the hole coverage rate, the adhesiveness and the resolution of the LDI dry film are improved, and the shape of the resist is improved.

Compared with the scheme that oxetane groups are not introduced into the alkali-soluble polymer, but oxetane group-containing monomers are introduced into free radical monomers in the LDI dry film preparation process, the invention has the advantages that the oxetane groups are introduced into the alkali-soluble polymer: the invention can further generate cationic crosslinking reaction inside the alkali-soluble polymer chain and between the alkali-soluble polymer chains; the comparative scheme does not involve any reaction within the alkali-soluble polymer, and only radical polymerization occurs between the radical monomers, which is the only choice for radical polymerization, with oxetane group-containing monomers.

In the alkali-soluble polymer of the present invention, the mass ratio of the oxetanyl group-containing polymerized unit in the alkali-soluble polymer is preferably 1 to 65%.

If the amount of oxetane groups is less than 1%, the amount of oxetane groups to be cationically polymerized is small, and a sufficient degree of crosslinking cannot be formed in the alkali-soluble polymer, so that the hardness and the adhesiveness of the LDI dry film cannot be enhanced well.

If it is higher than 65%, the amount of cationically polymerized oxetane groups can be increased, but at the same time the amount of other polymerized units can be reduced (e.g., a carboxyl group-containing polymerized monomer, other properties of the LDI dry film such as developability and flexibility can be reduced), thereby lowering the sensitivity, resolution, hole coverage and adhesion of the LDI dry film and affecting the resist shape.

According to the preparation method of the alkali-soluble polymer, the alkali-soluble polymer can be prepared, and the LDI dry film prepared by adopting the preparation method of the invention has good cover porosity, photosensitivity, resolution and adhesiveness; while having a good resist shape.

Drawings

FIG. 1 is a graph of the reaction mechanism of the alkali-soluble polymer and cationic initiator of the present invention upon direct laser exposure in an LDI dry film;

FIG. 2 is a graph showing the reaction mechanism of a prior art LDI dry film upon direct exposure to laser light;

FIG. 3 is a schematic diagram of the reaction equations of an alkali-soluble polymer and cationic initiator of the present invention when exposed directly to laser light in LDI dry film;

FIG. 4 is a nuclear magnetic resonance spectrum of the alkali-soluble polymer prepared in example 1 according to the preparation of the alkali-soluble polymer;

Fig. 5 is a graph showing the hardness of the LDI dry films prepared in comparative example 1 and examples 1 to 3 before and after exposure according to the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made more apparent and fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

According to an aspect of the present invention, there is provided an alkali-soluble polymer for preparing an LDI dry film, the side chain of the alkali-soluble polymer having oxetanyl groups; and is also provided with

The polymerized units containing oxetane groups account for 1-65% by mass of the alkali-soluble polymer.

On the one hand, under the initiation of a cationic initiator, the oxetane group on the side chain of the alkali-soluble polymer can be opened to generate a cationic crosslinking reaction between the inside of the polymer chain and the polymer chain when the side chain of the alkali-soluble polymer is provided with the oxetane group and the laser is directly exposed; on the other hand, cationic polymerization does not have the problems of oxygen inhibition and the like compared with free radical polymerization, and the LDI dry film shrinkage is small.

The LDI dry film containing the oxetane group and the cationic initiator is characterized in that the oxetane group is arranged in the side chain of the alkali-soluble polymer, when the LDI dry film is directly exposed by laser, the oxetane group arranged in the side chain of the alkali-soluble polymer is matched with the cationic initiator to generate cationic polymerization, and the inside of the alkali-soluble polymer chain and the polymer chain in the exposure area B are subjected to cationic polymerization to form a crosslinked network structure due to the ring opening of the oxetane group, wherein the reaction mechanism is shown in figure 1.

Wherein a is a monofunctional radical polymerizing monomer and/or a difunctional radical polymerizing monomer, b is an alkali-soluble polymer of the application, c is a multifunctional radical polymerizing monomer, d is a radical initiator and a cationic initiator; a is the unexposed dissolvable region; b is a photocrosslinked insoluble region after exposure.

In the prior art, oxetane groups are not introduced into the alkali-soluble polymer, but rather, in the preparation of the LDI dry film, oxetane group-containing compounds are introduced into the radical monomers. The invention can further carry out cationic crosslinking reaction between the inside of the alkali-soluble polymer chain and the polymer chain; the prior art solution does not involve any reaction within the alkali-soluble polymer chain and/or between the polymer chains, and only radical polymerization occurs between the radical monomers, which is the only choice of oxetane group-containing compound, and the reaction mechanism is shown in fig. 2.

Wherein a is a single-functional radical polymerization monomer and/or a double-functional radical polymerization monomer, b is an alkali-soluble polymer in the prior art, c is a multi-functional radical polymerization monomer, d is a radical initiator, and A is an unexposed soluble area; b is a photocrosslinked insoluble region after exposure.

According to the alkali-soluble polymer of the present invention, the mass ratio of the oxetane group-containing polymeric unit in the alkali-soluble polymer is preferably 1 to 65%.

According to the alkali-soluble polymer of the present invention, it is further preferable that the mass ratio of the oxetane group-containing polymeric unit in the alkali-soluble polymer: 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% and 65%.

According to one embodiment of the alkali-soluble polymer of the present invention, the polymeric monomer of the polymeric unit containing oxetane groups is represented by formula I and/or formula II:

preferably, n is a natural number from 1 to 3; further preferably 1 or 2.

One end of the formula I and the formula II contains double bonds and can be copolymerized with other polymerization monomers; the other end contains a four-membered ring, and ring-opening polymerization can occur.

When n is preferably 1 or 2, the peelability of the LDI dry film prepared using the alkali-soluble polymer of the present invention can be improved.

That is, the oxetane group-containing polymeric monomer is selected from at least one of the following:

(3-ethyloxetan-3-yl) methyl acrylate (which corresponds to a compound of formula I in which n is 1), and (3-ethyloxetan-3-yl) methyl methacrylate (which corresponds to a compound of formula II in which n is 1);

2- (3-ethyloxetan-3-yl) ethyl acrylate (which corresponds to a compound of formula I in which n is 2), 2- (3-ethyloxetan-3-yl) ethyl methacrylate (which corresponds to a compound of formula II in which n is 2);

3- (3-ethyloxetan-3-yl) propyl acrylate (which corresponds to the compound of formula I when n is 3), 3- (3-ethyloxetan-3-yl) propyl methacrylate (which corresponds to the compound of formula II when n is 3).

Among them, acrylic acid and methacrylic acid are preferable.

Preferably, the polyacrylic acid unit accounts for 1 to 50% of the total mass of the alkali-soluble polymer.

If the acid value is less than 1%, the development performance of the LDI dry film is poor due to the fact that the acid value is too low; if the amount is more than 50%, the resist may be poorly shaped, and the exposed region may be washed off.

Based on the above consideration, 1 to 35% is more preferable; still more preferably 1 to 30%; more preferably 1 to 25%; more preferably 1 to 20%.

Specifically, the polyacrylic acid units account for 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% of the total mass of the alkali-soluble polymer.

preferably, the polymeric monomer constituting the polyacrylate unit is selected from at least one of the following: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate.

According to the alkali-soluble polymer of the present invention, the acrylic acid ester monomer is preferably alkyl acrylate and alkyl methacrylate, and the peelability and alkali developability of the LDI film can be improved.

The alkyl acrylate may be represented by the formula III, wherein R1 represents a hydrogen atom or a methyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms.

As R in formula III ₁ Can be methyl or a hydrogen atom; r is R ₂ The alkyl group having 1 to 12 carbon atoms is selected from any one of the following groups: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and structural isomers thereof; methyl, ethyl, propyl and butyl are preferred.

The alkyl group is preferably an alkyl group having 4 or less carbon atoms (i.e., methyl, ethyl, propyl, and butyl group), and can improve the peelability of the LDI dry film.

That is, in the present invention, among the compounds represented by the above formula III, at least one selected from the following compounds may be added: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate.

And may also be selected from the following compounds: pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, octyl acrylate, octyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, nonyl acrylate, nonyl methacrylate, decyl acrylate, decyl methacrylate, undecyl acrylate, undecyl methacrylate, dodecyl acrylate and dodecyl methacrylate.

When alkyl acrylate and/or alkyl methacrylate is selected, it is preferable that the alkali-soluble polymer accounts for 1 to 80% by mass of the total mass of the alkali-soluble polymer, and in this range, the peelability and the adhesion of the LDI dry film can be improved.

If the content is less than 1%, the peeling property of the LDI dry film is poor; if the content is more than 80%, the adhesiveness, resolution and resist shape of the LDI dry film are poor; when the content is 1 to 80%, the dry film has good peelability, adhesion, resolution and resist shape.

From the above viewpoint, it is more preferably 2 to 70%, still more preferably 3 to 60%.

Specifically, it is preferable that: 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70% and 80%.

Wherein, preferably, the polymerization unit containing benzene ring accounts for 1-50% of the alkali-soluble polymer by mass percent.

If less than 1%, sufficient resolution is not easily obtained; if the amount is more than 50%, the release sheet becomes large and the release time becomes long.

Specifically, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% are preferable.

In the present application, in addition to the specific acrylic polymer monomer, and benzene ring-containing polymer monomer described above, the following polymer monomers may be used:

(1) Polymerizable styrene derivatives substituted on the α -position or aromatic ring such as vinyl toluene and α -methylstyrene;

(2) Acrylamide such as diacetone acrylamide;

(3) (meth) acrylic esters such as cycloalkyl (meth) acrylate, furfuryl (meth) acrylate, tetrahydrochysene (meth) acrylate, adamantyl (meth) acrylate, dicyclopentyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2-trifluoroethyl (meth) acrylate, and 2, 3-tetrafluoropropyl (meth) acrylate;

(4) (meth) acrylic acid derivatives such as α -bromo (meth) acrylic acid, α -chloro (meth) acrylic acid, β -glycosyl (meth) acrylic acid, β -styryl (meth) acrylic acid, and the like;

(5) Organic acid derivatives such as monomethyl maleate, maleic acid, and propiolic acid;

(6) Acrylonitrile.

It is to be noted that the inclusion of (methyl) in brackets in the above-mentioned (1) to (6) means that the compound is classified into two cases of containing methyl and not containing methyl; and so on hereinafter.

preferably, the acid value of the alkali-soluble polymer is 100 to 250mgKOH/g;

preferably, the alkali-soluble polymer has a dispersity of 1.0 to 8.0.

Wherein, the alkali-soluble polymer is used as one of the main components of the LDI dry film, if the weight average molecular weight of the alkali-soluble polymer is less than 10000Da, the LDI dry film is easy to wash away, even the exposure area is washed away; if the weight average molecular weight of the alkali-soluble polymer is more than 200000Da, the LDI dry film is too difficult to wash off and residue is caused; therefore, in the range, the LDI dry film of the exposure area is not easy to wash off; but also can make the non-exposure area be easily removed, and the effect is best.

Among them, the weight average molecular weight of the alkali-soluble polymer is particularly preferably 10000Da, 20000Da, 30000Da, 40000Da, 50000Da, 80000Da, 100000Da, 150000Da and 200000Da.

The alkali-soluble polymer is used as the main component of the LDI dry film, the LDI dry film needs to keep the glass transition temperature higher than 100 ℃, and the temperature is obviously higher than the temperature of the preservation and/or transportation environment, so that the LDI dry film has good stability, and the uneven thickness phenomenon caused by local flow, namely the cold flow phenomenon, is prevented.

Among them, the glass transition temperature of the alkali-soluble polymer is particularly preferably: 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃ and 150 ℃.

The acid value of the alkali-soluble polymer according to the present invention is preferably 100 to 250mgKOH/g.

When the acid value is less than 100mgKOH/g, the non-exposed region is not easily washed off by an alkali solution because the acid value is too low; when the acid value is higher than 250mgKOH/g, an excessively high acid value may cause the LDI dry film in the exposed region to be washed off.

The acid value of the alkali-soluble polymer according to the invention is preferably: 100mgKOH/g, 110mgKOH/g, 120mgKOH/g, 130mgKOH/g, 140mgKOH/g, 150mgKOH/g, 160mgKOH/g, 170mgKOH/g, 180mgKOH/g, 190mgKOH/g, 200mgKOH/g, 210mgKOH/g, 220mgKOH/g, 230mgKOH/g and 250mgKOH/g.

According to the alkali-soluble polymer of the present invention, the dispersion degree of the alkali-soluble polymer is preferably 1.0 to 8.0.

Further dispersity is preferably 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 and 8.0.

the alkali-soluble polymer provided by the invention adopts the four specific polymerization monomers, and has high reactivity ratio and high polymerization rate due to the similar structure; the prepared alkali-soluble polymer is used for preparing an LDI dry film, and has high photosensitivity, resolution, adhesiveness and cover porosity and good resist shape.

Preferably, the polymethacrylic acid units account for 5-50% by mass based on the total mass of the alkali-soluble polymer; 1-50% of polymethyl methacrylate units, 1-80% of polymethyl methacrylate units and 5-65% of poly (3-ethyloxetan-3-yl) methyl methacrylate.

Among them, the polymethacrylic acid units are more preferably 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50%.

Among them, more preferably 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% of the benzyl polymethacrylate units.

Among them, polymethyl methacrylate units are further preferably 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70% and 80%.

Among them, poly (3-ethyloxetan-3-yl) methyl methacrylate is further preferably 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% and 65%.

The alkali-soluble polymer in the above range is used for preparing LDI dry film, and has high photosensitivity, resolution, adhesiveness and cover porosity, and good resist shape.

According to the alkali-soluble polymer, after preparing the LDI dry film, a cationic initiator is matched, and when laser is directly exposed, the mechanism of cationic polymerization in the alkali-soluble polymer is shown in fig. 3:

The polymerized monomer comprises polymerized monomers containing oxetanyl, and the polymerized monomers account for 5 to 65 percent by mass percent;

preferably, the oxetane group-containing polymeric monomer is of formula I and/or formula II:

preferably, n is a natural number from 1 to 3;

according to one embodiment of the preparation method of the invention, the alkali-soluble polymerized monomer further comprises a polyacrylic monomer;

the acrylic polymerized monomer is selected from at least one of the following: acrylic acid, methacrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, and maleic half esters.

The alkali-soluble polymer obtained by the preparation method is used for preparing the LDI dry film, so that the LDI dry film with high sensitivity, resolution, adhesion and covering porosity and good resist shape is obtained.

In the preparation method of the invention, a semi-continuous polymerization process is preferably adopted, and the specific reference is made to examples, namely, the initiator and the monomer are dropwise added into the reaction system step by step, so that the reaction speed can be controlled, and the conversion rate is close to 100%.

The semi-continuous polymerization process is specifically as follows: dissolving a polymerization monomer in a part of solvent, adding a first part of free radical initiator, and marking as a solution a; dissolving a second portion of the free radical initiator in another portion of the solution, denoted solution b; under the protection of inert gas, adding the solution a into a three-neck flask with a mechanical stirrer and a reflux condenser, slowly dripping the solution b into the solution a, stirring to fully mix, and heating and polymerizing for a certain time; then dissolving a third part of free radical initiator in part of solvent, dripping the solution into the mixed solution, and cooling after preserving heat for a certain time; an alkali-soluble polymer solution was obtained.

According to one embodiment of the preparation process of the present invention, the chain transfer agent is selected from at least one of the following: dodecyl mercaptan, thioglycollic acid, isopropyl alcohol, sodium formate and sodium hypophosphite.

Preferably, the chain transfer agent is used in an amount of 0.1 to 5 mass% of the reaction monomer; further preferably 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0% and 5.0%.

According to one embodiment of the preparation process of the present invention, the free radical initiator is selected from at least one of the following: azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, azobicyclohexylcarbonitrile, dimethyl azobisisobutyrate, and even helium iso Ding Qingji formamide.

Preferably, the free radical initiator is used in an amount of 0.1 to 4% of the reaction monomer; further preferably 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 3.0% and 4.0%.

Preferably, the reaction temperature is 60-100 ℃; further preferably 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ and 100 ℃.

According to the preparation method, the chain transfer agent is added, so that the molecular weight of the alkali-soluble polymer is effectively regulated and controlled to 10000 Da-200000 Da; the molecular weight distribution range FDI is 1.0 to 8.0.

The alkali-soluble polymer obtained by the preparation method of the invention exists in the form of a solution, and the solvent is preferably ethylene glycol methyl ether, and other solvents can be selected, such as: butanone, toluene, propylene glycol methyl ether, ethylene glycol ethyl ether, propylene glycol ethyl ether, and the like.

The solid content of the alkali-soluble polymer solution is preferably 20 to 60%, more preferably 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%.

In the preparation method according to the present invention, the kinds and amounts of the selected polymeric monomers are the same as those of the alkali-soluble polymer according to the present invention, and are not described herein.

According to another aspect of the present invention, there is provided a cationic free radical polymerization composition for preparing an LDI dry film; comprising the following steps:

an alkali-soluble polymer;

a radical polymerizable compound;

an initiator; wherein, the liquid crystal display device comprises a liquid crystal display device,

the side chains of the alkali-soluble polymer have oxetanyl groups; and the polymerization unit containing oxetane group accounts for 5-65% of the alkali soluble polymer by mass percent; the initiator includes a radical initiator and a cationic initiator.

In the cationic free radical polymerization composition used in the present application to prepare the LDI dry film, the alkali soluble polymer of the present application is employed.

The selection and amount of the polymeric monomer used to prepare the alkali-soluble polymer are referred to in the preparation of the alkali-soluble polymer of the present invention and will not be described in detail herein.

Among them, the alkali-soluble polymer is preferably 30 to 70 parts by mass based on 100 parts by mass of the total amount of the composition for cationic radical polymerization for preparing the LDI dry film.

Wherein 30 to 70 parts of the alkali-soluble polymer means a solid solution in a solution in the form of a solution.

When less than 30 parts, the non-exposed area is not easily washed off, and the developability is poor; when the amount is more than 70 parts, the radical polymerizable compound is relatively reduced, and after the dry LDI film is produced, the adhesion and the hole coverage in the exposed region are poor after the laser exposure. In the range of 30 to 70 parts, the developing property, the adhesion and the pore-forming property are all good.

Further preferably 30 to 65 parts by weight based on the combination of the developability, the adhesion and the hole-covering property; more preferably 40 to 60 parts.

Specifically, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, and 65 parts are preferable.

Radical polymerizable monomer

According to one embodiment of the present invention, the radically polymerizable compound is a radically polymerizable compound having an ethylenically unsaturated group, and the radically polymerizable compound may be in the form of a monomer or a resin (including oligomers and prepolymers).

According to one embodiment of the present invention, the total amount of the radical polymerizable compounds is preferably 10 to 50 parts based on 100 parts of the cationic radical polymerizable composition.

Further preferred are 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts and 50 parts.

The radically polymerizable compound includes radically polymerizable monofunctional compounds, difunctional compounds, trifunctional or higher-functional compounds, and mixtures thereof; preferably a monofunctional compound, a mixture of a difunctional compound and a trifunctional compound or a mixture of two or more difunctional compounds.

Radical polymerizable monofunctional compound

The radically polymerizable monofunctional compound has a low viscosity and can be used as a photoreactive diluent, for example, an acrylic acid ester compound, a methacrylic acid ester compound, an acryl compound, a methacryl compound, an ethylene derivative, a styrene compound, an acid anhydride compound having an ethylenically unsaturated double bond (for example, maleic anhydride), N-vinylpyrrolidone, N-vinylformamide, or the like.

As the acrylic acid ester compound and the methacrylic acid ester compound, preferable are: C1-C18 alkyl acrylate, C1-C18 alkyl methacrylate; further preferred are C1-C6 alkyl acrylates, C1-C6 alkyl methacrylates, and still further preferred are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate and 2-methacryloxyphthalate.

Hydroxy-functionalized (meth) acrylates, such as hydroxy C1-C6 alkyl (meth) acrylates, particularly 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, glycidyl methacrylate, and the like, may also be used.

(meth) acrylic esters having a cyclic skeleton such as isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, gamma-butyrolactone (meth) acrylate, and tricyclodecanol (meth) acrylate may also be used.

Optionally, (meth) acrylates containing alkoxy modifications such as EO, PO, etc. (e.g. having 1 to 10, such as 2, 4, 6 or 8, preferably 1 to 5 EO and/or PO units), such as methoxy diethylene glycol (meth) acrylate, methoxy triethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate, may also be used.

Wherein the (meth) acryl group can be selected from acryl morpholine, 2-methacryl ethoxy succinate, N-dimethylacrylamide, N-diethylacrylamide and N, N-dipropylacrylamide.

As the styrene compound, chloromethyl styrene and alpha-methyl styrene can be selected.

As the acid anhydride containing an ethylenically unsaturated double bond, maleic anhydride or the like can be used.

As ethylene derivatives, vinyl esters, preferably vinyl esters of C2-C6 monocarboxylic acids, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl caproate or mixtures thereof, may be used.

The radical polymerizable difunctional compound may be selected from 5 to 35 parts by mass based on 100 parts by mass of the total amount of the cationic radical polymerizable composition for preparing the LDI dry film.

Radical polymerizable difunctional compound

The free radical polymerizable difunctional compound has higher reactivity than the monofunctional compound, and can improve the surface curability of the LDI dry film. The viscosity of the composition is lower than that of the free radical polymerizable trifunctional compound, and the composition can be used in combination with the monofunctional compound to serve as a diluent for the trifunctional and higher functional compounds, so that the LDI dry film viscosity of the composition containing the cationic free radical polymerization composition is reduced, and the reactivity is improved.

Radically polymerizable difunctional compounds, for example di (meth) acrylates of diols or triols having from 2 to 12, such as 2, 4, 6, 8 or 10 carbon atoms, di (meth) acrylates of polyethylene glycols or polypropylene glycols having a number average molecular weight of not more than 1,500, such as not more than 1,200. Wherein these compounds are optionally modified with EO or PO, e.g. with 5-15 EO and/or PO. Specifically selected from the group consisting of 2-hydroxy-3-acryloxypropyl (meth) acrylate, neopentyl glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 2-methyl-1, 3-butanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol di (meth) acrylate, 3-methyl-1, 5-pentanediol di (meth) acrylate, ethoxylated 1, 6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate, polyethylene glycol 400 di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol 400 di (meth) acrylate, polypropylene glycol 700 di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (200, polyethylene glycol di (meth) acrylate, polyethylene glycol (1000), ethoxylated polypropylene glycol 700 di (meth) acrylate, polypropylene glycol 400 di (meth) acrylate, bisphenol A di (meth) acrylate (which may contain different alkoxy segments such as EO, PO, etc.), hydrogenated bisphenol A di (meth) acrylate (which may contain different alkoxy segments such as EO, PO, etc.), dicyclopentadiene, 2-bis (4- (methacryloxypolyethoxy) phenyl) propane (average number of EO units is 5-15 per molecule). 1 or more than 2 of the above compounds may be selected.

Di (meth) acrylates of polyethylene glycols having a number average molecular weight of not more than 1,200 (e.g., not more than 800) and 2, 2-bis (4- (methacryloxypolyethoxy) phenyl) propane (average number of EO units of 5-15 per molecule) and mixtures thereof are preferred.

The radical polymerizable difunctional compound may be selected from 5 to 40 parts by mass based on 100 parts by mass of the total amount of the cationic radical polymerizable composition for preparing the LDI dry film.

The radical polymerizable compound having 3 or more functional groups may be selected from compounds having three or more (meth) acrylate groups.

The method can be specifically selected from the following steps: trimethylolpropane triacrylate, trimethylol methane triacrylate, ethylene oxide modified trimethylolpropane triacrylate, propylene oxide modified trimethylolpropane triacrylate, epichlorohydrin modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetra (meth) acrylate, tetramethylol methane tetraacrylate, ethylene oxide modified phosphoric acid triacrylate, propylene oxide modified phosphoric acid triacrylate, epichlorohydrin modified glycerol triacrylate, dipentaerythritol hexaacrylate, ditrimethylol propane tetraacrylate, or their silsesquioxane modifications, or their corresponding methacrylate monomers, epsilon caprolactone modified triacrylate, or the like.

The radical polymerizable trifunctional compound or more may be selected from 5 to 40 parts by mass relative to 100 parts by mass of the total amount of the cationic radical polymerizable composition for preparing the LDI dry film.

In one embodiment of the invention, the radically polymerizable compound is in the form of a resin (comprising an oligomer or prepolymer).

The radical polymerizable resin is preferably an epoxy (meth) acrylate resin, a polyester (meth) acrylate, a polyurethane (meth) acrylate, an ethylenically unsaturated polyester, an amino (meth) acrylate resin, or a photoimaging alkali-soluble resin.

The present invention preferably employs epoxy (meth) acrylate resins, polyester (meth) acrylates, polyurethane (meth) acrylates, or combinations thereof.

The epoxy (meth) acrylate resin is preferably bisphenol A epoxy (meth) acrylate, propylene glycol di (meth) acrylate-diluted bisphenol A epoxy acrylate or a combination thereof, such as bisphenol A epoxy acrylate WSR-U125 from a tin-free resin plant, 20% propylene glycol di-acrylate-diluted bisphenol A epoxy acrylate 621A-80 from Taiwan Changxing chemical company, modified bisphenol A epoxy acrylate 623-100 from Taiwan Changxing chemical company, and 20% propylene glycol di-acrylate-diluted modified bisphenol A epoxy acrylate 6231A-80 from Taiwan Changxing chemical company.

The polyester (meth) acrylates are preferably highly functional hyperbranched polyester acrylic resins, in particular hyperbranched polyester acrylic resins having a functionality of from 5 to 30, for example hyperbranched polyester acrylate prepolymers containing from 6 to 20 functionalities. For this, for example, hyperbranched polyester acrylate prepolymer 932-100 (6 functionality) from Cennoox, hyperbranched polyester acrylate prepolymer CN2300 (8 functionality), CN2301 (9 functionality), CN2302 (16 functionality) from Sa-Muma, USA may be used. The polyester (methyl) acrylate can be polyester polyol acrylic resin diluted by 20% of ethoxylated trimethylol propane triacrylate.

The polyurethane (meth) acrylate is preferably an aliphatic polyurethane acrylic resin. For this, aliphatic urethane diacrylate 611B-85 diluted with aliphatic urethane hexaacrylate 6145-100, 6161-100, 15%1, 6-hexanediol diacrylate (HDDA) of Taiwan Changxing chemical company, and aliphatic urethane diacrylate 6141H-80; aliphatic urethane acrylate CN9013 (9 functionality) from sandomax, us 15%1, 6-hexanediol diacrylate (HDDA) diluted aliphatic urethane acrylate CN966B85 (2 functionality), aliphatic urethane acrylate CN962 (2 functionality).

The total amount of the radical polymerizable compound is preferably 10 to 50 parts by mass relative to 100 parts by mass of the total amount of the cationic radical polymerizable composition for preparing the LDI dry film.

Initiator(s)

In the cationic radical polymerization composition of the present invention, the initiator includes a cationic initiator and a radical initiator.

(1) Cationic initiator

The cationic initiator is selected from at least one of the following: iodonium salt compounds, sulfonium salt compounds, and triazine compounds.

The iodonium salt compound is selected from at least one of the following: 4-isobutyl-4 '-methyl iodonium hexafluorophosphate, bis (4-dodecylphenyl) iodonium hexafluoroantimonate, bis (4-tert-butylphenyl) iodonium hexafluorophosphate, 4' -xylyliodonium hexafluorophosphate.

The sulfonium salt compound is selected from at least one of the following: triphenylsulfonium hexafluorophosphate, 4-phenylsulfanylphenyl diphenylsulfonium hexafluorophosphate, bis (4- (diphenylsulfonium) phenyl) sulfide-bis hexafluorophosphate.

The triazine compound is selected from at least one of the following: 2- (3, 4-Dimethoxyphenyl) -4, 6-bis (trichloromethyl) -1,3, 5-triazine, 2- (4-methoxyphenyl) -4, 6-bis (trichloromethyl) -S-triazine, 2- (1, 3-benzodioxol-5-yl) -4, 6-bis (trichloromethyl) -1,3, 5-triazine.

With the cationic initiator, in the case of direct laser exposure, cationic cross-linking polymerization can be performed between the inside of the alkali-soluble polymer chain and the polymer chain in the exposed region to form a cross-linked network.

The amount of the cationic initiator to be used is preferably 0.1 to 1 part by mass based on 100 parts by mass of the total amount of the composition for cationic radical polymerization for preparing the LDI dry film.

Further preferably 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part and 1.0 part.

The amount of cationic initiator used in the above range is sufficient to initiate cationic polymerization of the alkali-soluble polymer in the exposed areas.

(2) Free radical initiator

The free radical initiator may be hexaarylbiimidazole compound, quinone compound, aromatic ketone compound, acetophenone compound, acylphosphine oxide compound, benzoin ether compound, dialkyl ketal compound, thioxanthone compound, oxime ester compound, or acridine compound.

The hexaarylbiimidazole compound may be selected from 2- (o-chlorophenyl) -4, 5-diphenylbiimidazole, 2, 5-tris- (o-chlorophenyl) -4- (3, 4-dimethoxyphenyl) -4',5' -diphenylbiimidazole, 2, 4-bis- (o-chlorophenyl) -5- (3, 4-dimethoxyphenyl) -diphenylbiimidazole, 2,4, 5-tris- (o-chlorophenyl) -diphenylbiimidazole, 2- (o-chlorophenyl) -bis-4, 5- (3, 4-dimethoxyphenyl) -biimidazole, 2' -bis- (2-fluorophenyl) -4,4',5,5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 3-difluoromethylphenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 4-difluorophenyl) -4,4',5,5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 5-difluorophenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 6-difluorophenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 3, 4-trifluorophenyl) -4,4',5,5 '-tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 3, 5-trifluorophenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2 '-bis- (2, 3, 6-trifluorophenyl) -4,4',5,5 '-tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 4, 5-trifluorophenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2 '-bis- (2, 4, 6-trifluorophenyl) -4,4',5,5 '-tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 3,4, 5-tetrafluorophenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, 2 '-bis- (2, 3,4, 6-tetrafluorophenyl) -4,4',5,5 '-tetrakis- (3-methoxyphenyl) -diimidazole, 2' -bis- (2, 3,4,5, 6-pentafluorophenyl) -4,4', 5' -tetrakis- (3-methoxyphenyl) -diimidazole, and the like. Further preferred are 2- (o-chlorophenyl) -4, 5-diphenylimidazole dimers.

As the aromatic ketone compound, benzophenone, 4' -diethylaminobenzophenone and the like can be used.

The acetophenone compound can be selected from 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) -butanone-1, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholino-acetone-1.

The acyl phosphine oxide compound can be selected from 2,4, 6-trimethyl benzyl diphenyl phosphine oxide, bis (2, 4, 6-trimethyl benzoyl) -phosphine oxide and bis (2, 6-dimethoxy benzoyl) -2, 4-trimethyl-amyl phosphine oxide.

The thioxanthone compound can be selected from 2, 4-diethyl thioxanthone, 2, 4-diisopropyl thioxanthone and 2-chloro thioxanthone.

The oxime ester compound can be 1-phenyl-1, 2-propanedione-2-O-benzoyl oxime or 1-phenyl-1, 2-propanedione-2- (O-ethoxycarbonyl) oxime.

In the present invention, the total amount of the radical initiator is preferably 0.1 to 20 parts by mass based on 100 parts by mass of the total amount of the cationic radical polymerization composition for preparing the LDI dry film.

A radical initiator is preferably used, and a hexaarylbisimidazole compound is preferably used. Preferably 0.1 to 10 parts, more preferably 0.5 to 5 parts, are used.

Other ingredients

The cationic radical polymerization composition of the present embodiment may contain only the above components, or may contain other components in addition to the above components.

Other components can be sensitizer, hydrogen donor, leuco dye, basic dye and polymerization inhibitor.

The sensitizer may be selected from at least one of the following: pyrazoline compounds, anthracene compounds, acridine, triarylamine compounds, and oxazole compounds.

The hydrogen donor may be selected from at least one of N-arylamino acid compounds, mercapto compounds such as N-phenylglycine and mercaptobenzoxazole.

The leuco dye is selected from one of the following: colorless crystal violet (tris [4- (dimethylamino) phenyl ] methane), 3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide; colorless crystal violet is preferred.

The basic dyes are preferably basic green 1, malachite green oxalate and basic blue 7.

And a free radical polymerization inhibitor, wherein at least one of the following components is selected: p-methoxyphenol, hydroquinone, pyrogallol, naphthylamine, t-butylcatechol, cuprous chloride, 2, 6-di-t-butyl-p-cresol, 2 '-methylenebis (4-methyl-6-t-butylphenol), 2' -methylenebis (4-ethyl-6-t-butylphenol), triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate ], nitrosophenylhydroxylamine aluminum salts (for example, aluminum salts obtained by adding 3 moles of nitrosophenylhydroxylamine, etc.), diphenylnitrosoamine, and the like. Among them, preferred is an aluminum salt obtained by adding 3 moles of nitrosophenyl hydroxylamine to triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate ].

Cationic radical polymerization composition preparation liquid

In this embodiment, a solvent is added to the cationic radical polymerization composition, whereby a cationic radical polymerization composition-formulated liquid can be prepared.

Among them, methyl Ethyl Ketone (MEK), methanol, ethanol, and isopropanol are preferable.

The viscosity of the preparation liquid is 500 mPas to 4000 mPas at 25 ℃.

According to one aspect of the present invention, there is provided an LDI dry film comprising a support, a layer of cationic free radical polymeric composition disposed on the support, and a protective layer disposed on the layer of cationic free radical polymeric composition, the layer of cationic free radical polymeric composition comprising the cationic free radical polymeric composition of the present invention.

The preparation liquid of the cationic free radical polymerization composition is used as coating liquid, coated on the surface of a support, dried to form a cationic free radical polymerization composition layer, and covered with a protective layer on the surface of the cationic free radical polymer layer to obtain the LDI dry film.

Among them, the support may be a polyester such as polyethylene terephthalate, or a polymer film having heat resistance and solvent resistance such as polypropylene and polyethylene.

Wherein, the protective layer can be a polymer film such as polyethylene, polypropylene, etc.

The thickness of the cationic radical polymerization composition layer is not particularly limited and may be selected as required. The thickness of the dried material is generally 1-100 μm.

A PCB printing plate adopts LDI dry film of the application, and adopts LDI laser exposure to draw patterns.

For a more detailed description of the present invention, the present invention will be further described with reference to the following specific examples and the accompanying drawings. The examples are only for illustrating the present invention and do not limit the claims of the present invention.

Alkali-soluble Polymer preparation example 1

Polymerizing the monomers: 150g of methacrylic acid, 125g of benzyl methacrylate, 175g of methyl methacrylate, 50g of (3-ethyloxetan-3-yl) methyl methacrylate (mass ratio 30/25/35/10) were dissolved in 450g of ethylene glycol methyl ether as a solvent, and 2.5g of azobisisobutyronitrile was added thereto as a radical initiator, which was designated as a solution a. 0.25g of azobisbutyronitrile and 0.5g of dodecyl mercaptan as chain transfer agent were dissolved in 45g of ethylene glycol methyl ether as solution b. Solution a was added to a three-necked flask equipped with a mechanical stirrer and a reflux condenser under inert gas, solution b was slowly added dropwise to solution a over 0.5h, stirred to mix thoroughly, heated to 80℃and polymerized at 80℃for 12 hours. 0.5g of azobisisobutyronitrile was dissolved in 5g of ethylene glycol methyl ether, and the solution was added dropwise to the above mixed solution, and after heat preservation at 80℃for 2 hours, it was cooled to obtain an alkali-soluble polymer solution A-1.

The applicant carried out solid solution content detection on the alkali-soluble polymer solution A-1 by the following detection method: 5g of the alkali-soluble polymer solution A-1 was taken, placed in a glass petri dish, dried in a vacuum oven at 140℃for 4 hours, and the residual solid mass was measured and the solid content was calculated by comparison with the initial solution mass. To reduce test errors, all tests were performed simultaneously in at least three parallel sets of experiments.

The test result was that the solid content of the alkali-soluble polymer solution A-1 was 50% on average.

Comparing the test results with the ratio of the added polymerized monomer to the total mass of the solution, it can be seen that the added polymerized monomer is almost involved in the polymerization reaction.

The ratio of the polymerized units in mass percent in the alkali-soluble polymer in the present application thus corresponds to the ratio of the monomers corresponding to the polymerized units in mass percent in the total amount of monomers added.

In addition, the applicant carried out nuclear magnetic resonance detection on the prepared alkali-soluble polymer A-1, and the result is shown in FIG. 1.

As can be seen from FIG. 1, there are characteristic peaks of (3-ethyloxetan-3-yl) methyl methacrylate, wherein characteristic peaks of methylene group in oxetane can be seen remarkably (refer to characteristic peak marks 16 and 17 in FIG. 1, chemical shift is about 4.5 ppm); characteristic peaks of benzene rings (see characteristic peak mark 12 in FIG. 1, chemical shifts of 6.5 to 7.5 ppm) are also clearly seen.

Alkali-soluble Polymer preparation examples 2 to 5

The proportions of the polymerized monomers of preparation examples 2 to 5 are shown in Table 1, and the alkali-soluble polymer solutions A2, A3, A4 and A5 were obtained, respectively, under the same conditions as in preparation example 1.

Alkali-soluble Polymer preparation examples 6 to 8

The polymerization monomers of preparation examples 6 to 8 are shown in Table 1, except that the specific compound of oxetane methacrylate is changed, and alkali-soluble polymers A6, A7 and A8 are obtained in the same manner as in preparation example 5.

Alkali-soluble Polymer preparation example 9

The polymerized monomer of preparation example 9 was the same as in preparation example 7, except that no chain transfer agent was added, and the conditions were the same as in preparation example 7; the alkali-soluble polymer A9 was obtained.

Alkali-soluble Polymer preparation example 10

The polymerized monomer of production example 10 was the same as in production example 8, except that no chain transfer agent was added, and the conditions were the same as in production example 8, to obtain an alkali-soluble polymer a10.

Alkali-soluble Polymer preparation comparative examples 1 and 2

The ratio of the polymerization monomers is shown in Table 1, and the other conditions are the same as in preparation example 1, to obtain alkali-soluble polymer solutions D1 and D2.

Alkali-soluble Polymer preparation of comparative examples 3 and 4

The ratio of the polymerization monomers is shown in Table 1, and the other conditions are the same as in preparation example 1, to obtain alkali-soluble polymer solutions D3 and D4.

The alkali-soluble polymers produced in preparation examples 1 to 10 and preparation comparative examples 1 to 4 were measured by the following methods, and the measurement results are shown in table 1.

(1) Acid value measurement

1g of an alkali-soluble polymer was dissolved in 50ml of a mixed solvent (methanol 20%, acetone 80%), 2 drops of a 1% phenolphthalein indicator were added dropwise, and titration was performed with a 0.1mol/L KOH standard solution, whereby the acid value was measured.

(2) Determination of molecular weight and PDI

The weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene were measured by gel permeation chromatography (Waters: waters 707). The alkali-soluble polymer obtained in the above preparation examples and comparative examples was dissolved in tetrahydrofuran to give a concentration of 4000ppm, and 100. Mu.l was injected into GPC. The mobile phase of GPC was flown in with tetrahydrofuran at a flow rate of 1.0ml/min, and analysis was carried out at 35 ℃. Four of Waters HR-05, 1, 2, 4E were connected in series as a chromatographic column. The assay was performed using a RI and PAD Detector detector at 35 ℃. At this time, the PDI (polydispersity index) is calculated by dividing the measured weight average molecular weight by the number average molecular weight.

(3) Determination of the glass transition temperature

The glass transition temperature was measured using a differential scanning calorimeter (Differential scanning calorimeter, DSC, mettler Toledo, switzerland) under a nitrogen atmosphere at a temperature ranging from-70℃to 500℃and a heating rate of 10℃per minute. The method comprises the following specific steps: the temperature was first raised from room temperature to 150 ℃, then rapidly lowered to-70 ℃ to eliminate the thermal history of the sample, and then raised to 500 ℃.

The glass transition temperatures of all examples were measured by this method and were in the range of 100 to 150℃with the glass transition temperature of example 5 being 132 ℃.

TABLE 1

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As can be seen from the test results in Table 1, the acid values in the preparation examples 1 to 10 are all 100 to 250mgKOH/g, the weight average molecular weight is 10000 to 200000Da, and the PDI is 1 to 8.0; the alkali-soluble polymer thus prepared is suitable for the preparation of dry LDI films.

As can be seen from the comparison of preparation example 9 with preparation example 7, preparation example 7 with the addition of the chain transfer initiator has a better PDI dispersity than preparation example 9 without the addition of the chain transfer initiator.

It can also be seen from the comparison of preparation example 10 with preparation example 8 that preparation example 8 with the addition of the chain transfer initiator has a better PDI dispersion than preparation example 10 without the addition of the chain transfer initiator.

Preparation of a preparation solution and LDI Dry film of cationic free radical polymerization composition

The alkali-soluble polymer obtained in the above preparation example was designated as a, the alkali-soluble polymer obtained in the preparation comparative example was designated as D, the radical polymerizable compound was designated as B, the radical initiator and the cationic initiator were designated as C, wherein the cationic initiator was designated as C4, and the other was designated as E, and the amounts shown in table 2 were used to prepare the preparation solutions of the cationic radical polymerization compositions.

(B) Radical polymerizable compound

B1:2, 2-bis (4- (methacryloxypolyethoxy) phenyl) propane (EO group: 10mol (average)) (manufactured by Xinzhongcun chemical industry Co., ltd., "BPE-500")

B2: polyethylene glycol 400 dimethacrylate (New Zhongcun chemical industry Co., ltd., 9G)

(C) Initiator(s)

Radical initiator:

c1: EMK (tetraethyl mikudo, available from Hubei solid wetting technologies Co., ltd.),

c2: HABI-101 (2, 2' -bis (2-chlorophenyl) -4,4', 5' -tetraphenylbisimidazole [2- (2-chlorophenyl) -4, 5-diphenylimidazole dimer, available from Hemsl materials Co., ltd.),

and C3: NPG (N-phenylglycine, available from Youzhou powerful New materials Co., ltd.).

The cationic initiator is as follows:

and C4: and C4: GR-IS-4 (4, 4' -t-butylphenyl iodonium hexafluorophosphate, available from Hubei solid wetting technologies Co., ltd.).

Other components:

e1: basic green 1, available from Ann Ji reagent Co., ltd.

E2: LCV is colorless crystal violet, purchased from the company, powerful new materials, ltd, for discoloration upon illumination.

Preparation of LDI Dry film

The alkali-soluble polymers of preparation examples 1 to 5, the alkali-soluble polymers of preparation comparative examples 1 to 4, the radical polymerizable compounds, the radical initiator and the cationic initiator and other ingredients were added to a solvent according to the following Table 2, stirred at room temperature for 4 hours, and the impurities were removed by a 200-mesh filter to obtain the preparation solutions of examples 1 to 7 and comparative examples 1 to 4 of the cationic radical polymerization composition, i.e., coating solutions.

In addition, examples 1 to 7 and comparative examples 1 to 4 of the cationic radical polymerization composition, a laser scanning exposure apparatus having a wavelength of 355nm was used in evaluating the performance of the LDI dry film.

The preparation solutions of examples 1 to 7 and comparative examples 1 to 4 of the cationic radical polymerization compositions were uniformly coated on a PET supporting film layer having a thickness of 20. Mu.m, dried for 5 minutes by a hot air convection dryer at 100℃and then thermally bonded to a PE film having a thickness of 18. Mu.m, using a rubber roll, to thereby obtain an LDI dry film.

Wherein the film thickness of the cationic radical polymerization composition layer after drying was 40. Mu.m.

The cationic free radical polymerized composition layer components of the LDI dry films are shown in table 2.

TABLE 2

The cationic radical polymerization composition prepared according to the above composition was laminated to obtain an experimental substrate, and then subjected to a series of performance tests.

Lamination

By hot pressing, the substrate was preheated to 120℃at a roller temperature of 110℃and a laminating roller temperature of 4.0kgf/cm ² A test substrate was obtained by laminating the composition layer on the copper surface of the treated substrate using a heated roll while peeling the protective PE film at a roll speed of 1.5 m/min.

Testing of sensitivity

A41-grid step exposure rule (exposure rule concentration range 0.00-2.00, concentration step 0.05, exposure surface plate (rectangle) size 20mm X187 mm, each grid (rectangle) size 3mm X12 mm) was placed on the composition layer of the above test substrate, and then examples 1-7 and comparative examples 1-4 were each exposed with three different exposure energies by using a laser scanning exposure device having a wavelength of 355 nm. The PET film was then peeled off, developed with 1.0% by weight aqueous sodium carbonate solution at 30℃to remove the unexposed portion, and the number of residual exposed squares of the film formed on the copper-clad substrate was measured by observation to evaluate the sensitivity of the composition layer. The sensitivity is determined by the exposure energy (unit: mJ/cm) of the residual step number of 20 ² ) The lower the value, the better the sensitivity is indicated. The results are shown in Table 3.

Testing of resolution

The laminated composition layer of the test substrate was exposed to light with an exposure energy of 20 g remaining number of cells after development with a 41 g exposure rule using a drawing pattern having a line width (L)/pitch (S) (hereinafter referred to as "L/S") of 10/10 to 60/60 (unit: μm). After development treatment under the same conditions as the above-described evaluation of sensitivity, the resist pattern was observed with an optical microscope, and the minimum value of the space width between line widths generated by the line in which meandering and chipping did not occur was taken as the resolution. The analysis was evaluated as a smaller value, and the results are shown in table 3.

Testing of adhesion

On the composition layer of the test substrate after lamination, the drawing patterns of the same Line pitch and different Line widths were used in a Line/space=n/400 μm (n ranges from 5 to 51, and increases by 3 each time), and the exposure was performed with an exposure energy of 20 remaining cells after development with a 41-cell exposure rule. After development treatment under the same conditions as those for the above evaluation of sensitivity, the resist pattern was observed with an optical microscope, and the adhesion (μm) was evaluated by the minimum line width value remaining without peeling and creasing. The smaller the number, the better the adhesion. The results are shown in Table 3.

Testing of resist shape

The composition layer of the laminated test substrate was exposed to light with a residual exposure level of 20 g after development using a Litsea 41 g exposure ruler using a drawing pattern having a line width (L)/space (S) (hereinafter referred to as "L/S") of 5/5 to 60/60 (unit: μm). After development treatment under the same conditions as those for the evaluation of the above-described sensitivity, the developed resist pattern was subjected to topography observation by using a scanning electron microscope S8100 of japan hitachi company. It is very important that the resist shape is excellent. If the cross-sectional shape of the resist is trapezoidal or inverted trapezoidal or the bottom of the resist is tailing, a circuit formed by a subsequent etching process or plating process may be short-circuited, open-circuited, and thus the cross-sectional shape of the resist pattern after development is preferably rectangular in shape and free from bottom tailing. The case where the bottom smear is observed in the resist pattern is referred to as "bottom smear", and the case where the development residue is observed is referred to as "development residue". Here, "bottom tailing" means that, in the case where the cross-sectional shape of the resist pattern is observed, the developed resist pattern formed on the surface of the substrate copper foil is not rectangular but is tailing at the bottom of the gap portion (unexposed portion). The "development residue" refers to a state in which, when the cross-sectional shape of the resist pattern is observed, the developed resist pattern is not rectangular but has a significant bottom tailing, and the development residue remains in the gap portion, so that the lines are buried. The results are shown in Table 3.

Hole masking performance test

A copper plating substrate with the thickness of 1.6mm is provided with a triple special-shaped hole with the diameter of 6mm and the length of 12, 14 and 16mm respectively, after the double-sided hot-pressing lamination of the sensing composition layer, the double-sided hot-pressing lamination is carried out after the double-sided hot-pressing lamination is carried out, the double-sided hot-pressing lamination is carried out after the double-sided hot-pressing lamination is carried out for 4 times with the development after the double-sided hot-pressing has the length of 36s, the copper plating is carried out for 4 times after the exposure is carried out for the time with; and counting the number of broken holes of the special-shaped holes after development. The test results are shown in Table 3.

TABLE 3 Table 3

As can be seen from table 3, examples 1 to 7 were superior to comparative examples 1 and 2 in the sensitivity, resolution, adhesion, and resist shape of the LDI dry film.

This is because examples 1 to 7 use an alkali-soluble polymer having oxetanyl groups in the side chains of the present application, and the alkali-soluble polymer and a cationic initiator are combined to form a cationic radical polymerization compound, and an LDI dry film prepared from the composition can undergo crosslinking between the inside of the alkali-soluble polymer chain and the alkali-soluble polymer chain during laser exposure, thereby forming a network structure, and improving the hardness and the cohesiveness of the LDI dry film; further, the sensitivity, the hole coverage, the resolution and the adhesion are improved, and the resist shape is improved.

In comparative examples 1 and 2, the alkali-soluble polymer having no oxetanyl group in the side chain was not able to undergo cationic polymerization in combination with a cationic initiator, and the hardness and the adhesion of the LDI dry film were relatively poor, so that the resultant LDI dry film was relatively poor in photosensitivity, resolution, pore-coverage property, adhesion and resist shape.

As can be seen from table 3, examples 1 to 7 were superior to comparative examples 3 and 4 in sensitivity, resolution, adhesion, and resist shape of the obtained LDI dry films.

This is because the mass percentage of the oxetane group-containing polymerization unit in examples 1 to 7 is within 1 to 65%, whereas comparative examples 3 and 4 are less than 1% and more than 65%, respectively.

It can also be seen that the mass percentage of polymerized units containing oxetane groups in the alkali-soluble polymer is preferably 1 to 65%.

To further illustrate the invention, the inventors also conducted comparative tests of pencil hardness before and after exposure of LDI dry films according to GB-T6739-2006, the test results being shown in FIG. 2.

As can be seen from fig. 2, the LDI dry films of examples 1 to 3 all adopt the cationic radical polymerization composition of the present application, and the cationic initiator is matched to crosslink between the inside of the alkali-soluble polymer chain and between the polymer chains after laser direct exposure, so that the hardness of the dry films is greatly improved after exposure compared with that before exposure; comparative example 1, which does not employ the cationic radical polymerization composition of the present application, cannot crosslink with the cationic initiator after laser direct exposure, and has little change in hardness after and before exposure; further, as can be seen from fig. 3, the hardness after exposure was higher in each of examples 1 to 3 than in comparative example 1. In summary, it can be seen that the hardness after exposure is greatly improved compared with the prior art by adopting the LDI dry film of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. The cationic free radical polymerization composition for preparing the LDI dry film comprises, by mass, based on 100 parts of the total composition, 30-70 parts of alkali-soluble polymer, 10-50 parts of free radical polymerizable compound, 0.1-1 part of cationic initiator and 0.1-20 parts of free radical initiator;

wherein the polymerization unit of the alkali-soluble polymer consists of a polymerization unit containing oxetane groups, a polyacrylic acid unit, a polyalkylacrylate unit and a polymerization unit containing benzene rings;

the polymerized monomer of the polymerized unit containing oxetane group is shown as a formula I and/or a formula II:

n is a natural number of 1 to 3;

the polymerization unit containing oxetane groups accounts for 1-65% of the alkali-soluble polymer by mass percent;

the polymeric monomers constituting the polyacrylic acid units are acrylic acid and/or methacrylic acid; the polyacrylic acid units account for 1-50% of the alkali-soluble polymer in percentage by mass;

The polymerized monomer constituting the polyalkylacrylate unit is selected from at least one of the following: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate; the polyalkyl acrylate unit accounts for 1-80% of the alkali-soluble polymer in percentage by mass;

the polymerization monomer constituting the benzene ring-containing polymerization unit is selected from at least one of the following: benzyl acrylate, benzyl methacrylate, styrene; the benzene ring-containing polymerization unit accounts for 1-50% of the alkali-soluble polymer in percentage by mass.

2. The cationic free-radical polymerization composition according to claim 1, wherein the composition further comprises other ingredients selected from at least one of sensitizer, hydrogen donor, leuco dye, base dye, polymerization inhibitor.

3. The cationic radical polymerization composition according to claim 1, wherein the polymerization unit constituting the alkali-soluble polymer is composed of a polymethacrylic acid unit, a benzyl methacrylate unit, a polymethyl methacrylate unit and a poly (3-ethyloxetan-3-yl) methyl methacrylate unit.

4. The cationic radical polymerization composition according to claim 3, wherein the polymethacrylic acid unit accounts for 5% -50% by mass based on the total mass of the alkali-soluble polymer; the poly (benzyl methacrylate) unit accounts for 1% -50%, the poly (methyl methacrylate) unit accounts for 1% -80%, and the poly (3-ethyloxetan-3-yl) methyl methacrylate accounts for 1% -65%.

5. The cationic free-radical polymerization composition according to any one of claim 1 to 4,

the weight average molecular weight of the alkali-soluble polymer is 10000-200000 Da;

the glass transition temperature of the alkali-soluble polymer is 100-150 ℃;

the acid value of the alkali-soluble polymer is 100-250 mgKOH/g;

the dispersity of the alkali-soluble polymer is 1.0-8.0.

6. An LDI dry film comprising a support, a layer of cationic free radical polymeric composition disposed on the support and a protective layer disposed on the layer of cationic free radical polymeric composition, wherein the layer of cationic free radical polymeric composition comprises the cationic free radical polymeric composition of any one of claims 1-5.