KR102507402B1 - Manufacturing method of acrylic polymer using thermally free-radical polymerization without solvent, acrylic polymer manufactured therefrom and acrilic adhesive composition containing the same - Google Patents

Abstract

본 발명의 제조방법에 따라 무용제 자유 라디칼 열중합을 이용한 아크릴계 중합체의 제조시 이용되는 화학식 1의 사슬 이동제는 악취나 독성이 없고 적절한 분자량과 다분산도를 갖는 아크릴계 중합체의 제조가 가능하게 한다. 이렇게 제조된 아크릴계 중합체는 전자제품 등에 적용되는 아크릴계 접착제 조성물의 성분으로서 유용하다.The present invention is a method for producing an acrylic polymer by free radical thermal polymerization of a non-solvent acrylic monomer composition comprising a thermally polymerizable acrylic monomer, a free radical thermal initiator and a chain transfer agent, wherein the chain transfer agent is a silane chain transfer agent represented by Formula 1 Disclosed is a method for producing an acrylic polymer using solvent-free free radical thermal polymerization, characterized in that:
<Formula 1>

The chain transfer agent of Chemical Formula 1, which is used in the production of acrylic polymers using solvent-free free radical thermal polymerization according to the preparation method of the present invention, enables the preparation of acrylic polymers without odor or toxicity and having appropriate molecular weight and polydispersity. The acrylic polymer prepared in this way is useful as a component of an acrylic adhesive composition applied to electronic products and the like.

Description

Method for producing an acrylic polymer using solvent-free free radical thermal polymerization, an acrylic polymer prepared therefrom, and an acrylic adhesive composition comprising the same THE SAME}

The present invention relates to a method for preparing an acrylic polymer using free radical thermal polymerization without substantially using a solvent, an acrylic polymer prepared therefrom, and an acrylic adhesive composition comprising the same.

As adhesives, rubber-based adhesives, acrylic adhesives, vinyl ether-based adhesives, silicone-based adhesives, and the like have been used. Among them, acrylic adhesives containing acrylic polymers as a main component are used in various fields because of their excellent weatherability and oxidative deterioration.

As methods for producing acrylic polymers, solution polymerization, suspension polymerization, emulsion polymerization, solvent-free free radical (thermal) polymerization and the like are used.

Solution polymerization, suspension polymerization and emulsion polymerization methods are disadvantageous in that they require special equipment and special processing. Solution polymerization, suspension polymerization and emulsion polymerization have lower production rates than solvent-free free radical (thermal) polymerization for a given reactor capacity. Emulsion polymerization and suspension polymerization have the potential to introduce contaminants into the polymer from surfactants and/or emulsifiers used in the polymerization process. In addition, contaminants may be introduced through various impurities in the solvent in solution polymerization. Moreover, in the case of solution polymerization, the solvent used is dangerous because of fear of fire and/or explosion. It can be costly because special equipment is required to recover the solvent for reuse of the used solvent, or materials such as thermal oxidizers must be used to prevent the compound from being released into the atmosphere. The solvent-free free radical thermal polymerization method can minimize the aforementioned problems.

Acrylic adhesives, which are used in various fields because of their excellent weather resistance and oxidative degradation, have acrylic polymers as their main component, and the acrylic polymers are made by adding a solvent-free acrylic monomer composition containing a thermally polymerizable acrylic monomer, a free radical thermal initiator, and a chain transfer agent to free radical heat. It can be prepared by polymerization. A chain transfer agent is a molecular weight control agent, which suppresses an excessive increase in molecular weight of the polymer produced and allows it to have a narrow molecular weight distribution. Chain transfer agents used in the production of acrylic polymers include thiol compounds such as n-dodecyl mercaptan and isooctyl thioglycolate, halogen compounds such as tetrabromide and hexane bromoethane, and aromatic hydrocarbons.

When using a chain transfer agent containing sulfur or halogen, problems such as corrosion of electrodes may be caused when the obtained acrylic polymer is applied to electronic products. In addition, sulfur-containing chain transfer agents and the like have a bad odor or are toxic.

Therefore, the problem to be solved by the present invention is a method for preparing an acrylic polymer by free radical thermal polymerization of a solvent-free acrylic monomer composition, a chain transfer agent that does not cause odor or toxicity and does not cause electrode corrosion when applied to electronic products. It is to provide a method for producing an acrylic polymer using and an acrylic polymer prepared therefrom.

Another problem to be solved by the present invention is to provide an acrylic adhesive composition comprising the above-described acrylic polymer.

In order to solve the above-described technical problem, the manufacturing method according to the first embodiment of the present invention prepares an acrylic polymer by free radical thermal polymerization of a solvent-free acrylic monomer composition including a thermally polymerizable acrylic monomer, a free radical thermal initiator, and a chain transfer agent. As a method, the chain transfer agent provides a method for producing an acrylic polymer using solvent-free free radical thermal polymerization, characterized in that the silane-based chain transfer agent represented by Formula 1:

In Formula 1,

R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, a hydroxyl group, an alkoxyl group, a silyl group, an amino group and a glycidyl group.

In the method for producing an acrylic polymer according to the first embodiment, the silane-based chain transfer agent of Formula 1 is a group consisting of triethylsilane, dimethylphenylsilane, tris(trimethylsilyl)silane, pentamethyldisilane and triisopropylsilane. It may be at least one selected from, and in particular, it may be at least one of triethylsilane and pentamethyldisilane. The content of the silane-based chain transfer agent may be 0.01 to 10 parts by weight based on 100 parts by weight of the thermally polymerizable acrylic monomer.

According to the second embodiment of the present invention, the thermally polymerizable acrylic monomer in the first embodiment may be branched or unbranched (meth)acrylic acid or a derivative thereof having 1 to 20 carbon atoms, and particularly alkyl (meth)acrylates. , It may be at least two or more selected from the group consisting of alicyclic (meth)acrylate and hydroxy (meth)acrylate.

According to the third embodiment of the present invention, in any one or more of the first embodiment or the second embodiment, the thermally polymerizable acrylic monomer may include a thermally polymerizable acrylic monomer having a photoreactive group. The photoreactive group may be a benzophenone group. For example, the thermally polymerizable acrylic monomer having a benzophenone group is selected from the group consisting of benzophenone methacrylate, 6-(4-benzoylphenoxy)hexyl methacrylate, and benzophenone acrylate. It may be at least one type.

According to the fourth embodiment of the present invention, in any one or more of the first to third embodiments, the weight average molecular weight of the acrylic polymer is 10,000 to 800,000 g/mol, and the polydispersity is 1.5 to 5.0 can be

The acrylic polymer prepared by the above method is useful as a component of an acrylic adhesive composition applied to electronic products and the like.

The chain transfer agent of Chemical Formula 1 used in the preparation of acrylic polymers using solvent-free free radical thermal polymerization according to the production method of the present invention has no odor or toxicity. In addition, when the acrylic polymer prepared therefrom is applied to electronic products, it does not cause problems such as corrosion of electrodes.

In addition, it is possible to prepare an acrylic polymer having an appropriate molecular weight and polydispersity when preparing an acrylic polymer by using solvent-free free radical thermal polymerization using the chain transfer agent of Chemical Formula 1.

Therefore, the acrylic polymer prepared in this way is useful as a component of an acrylic adhesive composition applied to various fields such as electronic products.

Hereinafter, the present invention will be described in detail. The terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to explain their invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

In the present invention, "acrylic" means branched or unbranched acrylic acid or methacrylic acid or derivatives thereof. In addition, "(meth)acrylic acid" or "(meth)acrylate" is meant to include both acrylic acid and methacrylic acid, and acrylate and methacrylate, respectively.

In the present invention, solvent-free free-radical thermal polymerization is based on being carried out without a solvent, that is, in the form of pure bulk polymerization in which not only the formed polymer but also all the monomers are self-mixed, in order to (co)polymerize some small amount of monomers This is meant to include cases where a non-reactive solvent is required (20% or less based on the total weight of the polymerizable monomer composition).

Hereinafter, a method for producing an acrylic polymer using non-solvent free radical thermal polymerization according to the present invention will be described.

The present invention relates to a method for preparing an acrylic polymer by free radical thermal polymerization of a non-solvent acrylic monomer composition comprising a thermally polymerizable acrylic monomer, a free radical thermal initiator and a chain transfer agent, wherein the chain transfer agent is a silane chain transfer agent represented by Formula 1 below. Use

<Formula 1>

In Formula 1,

R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, a hydroxyl group, an alkoxyl group, a silyl group, an amino group and a glycidyl group.

A chain transfer agent, as a molecular weight regulator, is an additive that inhibits polymerization of a polymer with an excessively high molecular weight and has a narrow molecular weight distribution during polymer production. When conventional thiol compounds such as n-dodecyl mercaptan and isooctyl thioglycolate or halogen compounds such as tetrabromide and hexane bromoethane are used as chain transfer agents in the production of acrylic polymers, the obtained acrylic polymers are applied to electronic products. When used, it may cause problems such as corrosion of electrodes. In addition, sulfur-containing chain transfer agents and the like have a bad odor or are toxic.

The present inventors minimized the disadvantages of using solution polymerization, suspension polymerization, and emulsion polymerization methods by using solvent-free free radical thermal polymerization when preparing acrylic polymers, and when using the silane-based compound of Formula 1 without odor or toxicity as a chain transfer agent, It was confirmed that the function as a chain transfer agent was effectively performed, and the present invention was completed.

In a specific embodiment of the present invention, the silane-based chain transfer agent of Chemical Formula 1 is triethylsilane of Chemical Formula 2, dimethylphenylsilane of Chemical Formula 3, tris(trimethylsilyl)silane of Chemical Formula 4, or of Chemical Formula 5 below. It may be at least one selected from the group consisting of pentamethyldisilane and triisopropylsilane represented by Formula 6 below, and in particular, at least one selected from triethylsilane and pentamethyldisilane.

The content of the silane-based chain transfer agent may be, for example, 0.01 to 10 parts by weight, particularly 0.05 to 6 parts by weight, based on 100 parts by weight of the thermally polymerizable acrylic monomer. More specifically, the content of triethylic acid may be 0.05 to 6 parts by weight, the content of dimethylphenylsilane may be 0.05 to 3 parts by weight, the content of tris (trimethylsilyl)silane may be 0.05 to 1 part by weight, , The content of pentamethyldisilane may be 0.05 to 2 parts by weight, and the content of triisopropylsilane may be 1 to 4 parts by weight.

In the method for producing an acrylic polymer using non-solvent free radical thermal polymerization according to the present invention, the thermally polymerizable acrylic monomer may be, for example, branched or unbranched (meth)acrylic acid or a derivative thereof having 1 to 20 carbon atoms. , but not limited thereto. In particular, the thermally polymerizable acrylic monomer may be at least two or more selected from the group consisting of alkyl (meth)acrylates, alicyclic (meth)acrylates, and hydroxyl (meth)acrylates. Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t- Butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth)acryl One or more types of acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate, and tetradecyl (meth)acrylate may be used, but is not limited thereto. As the alicyclic (meth)acrylate, one or more of cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and the like may be used, but is not limited thereto. Examples of hydroxy (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, One or more of acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol (meth)acrylate, etc. may be used, but is not limited thereto. .

Free radical thermal initiators Many free radical thermal initiators that can be used are known in the art of acrylic monomer polymerization and can also be used in the present invention. Typical thermal free radical polymerization initiators useful in the present invention include organic peroxides, organic hydroperoxides and azo initiators that generate free radicals. Useful organic peroxides include, but are not limited to, compounds such as benzoyl peroxide, di-t-amyl peroxide, t-butyl peroxy benzoate and di-cumyl peroxide. Useful organic hydroperoxides include, but are not limited to, compounds such as t-amyl hydroperoxide and t-butyl hydroperoxide. Useful azo group initiators include VAZO (trade name) compounds from DuPont, for example VAZO (trade name) 52 (2,2'-azobis (2,4-dimethylpentanenitrile)), VAZO (trade name) 64 (2 ,2'-azobis (2-methylpropanenitrile)), Vazo (trade name) 67 (2,2'-azobis (2-methylbutanenitrile)), and Vazo (trade name) 88 (2,2'-azo bis(cyclohexanecarbonitrile)), but is not limited thereto. The content of the free radical thermal initiator may be included in the composition at 0.01 part by weight to 20 parts by weight based on 100 parts by weight of the monomer component, but it may be changed in consideration of process efficiency or physical properties of the polymer.

In a specific embodiment of the present invention, the acrylic monomer having a benzophenone group may be, for example, branched or unbranched (meth)acrylic acid or a derivative thereof having a benzophenone group and having 1 to 20 carbon atoms, and more specifically may be at least one selected from the group consisting of benzophenone methacrylate, 6-(4-benzoylphenoxy)hexyl methacrylate, and benzophenone acrylate, but is not limited thereto.

In one specific embodiment of the present invention, the thermally polymerizable acrylic monomer may include a thermally polymerizable acrylic monomer having a photoreactive group. Examples of the photoreactive group include, but are not limited to, known photoreactive groups such as a benzophenone group. acrylate, benzophenone acrylate, and the like, and at least one or more of these can be used. A polymerized acrylic polymer including a thermally polymerizable acrylic monomer having a photoreactive group may be used as a component of a photocurable acrylic adhesive composition used in a hot melt acrylic adhesive or the like together with a photoinitiator.

The acrylic monomer composition having such a composition is a solvent-free acrylic monomer composition that does not substantially use a solvent, and free-radical thermal polymerization is possible without a solvent, and the acrylic polymer having an excessively high molecular weight and the molecular weight distribution is not wide, preferably the weight average of the acrylic polymer. It may be made of an acrylic polymer having a molecular weight of 10,000 to 800,000 g/mol and a polydispersity of 1.5 to 5.0, particularly a polydispersity of 2 to 4.3.

Hereinafter, examples will be described in detail to explain the present invention in detail. However, the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

<Evaluation of average molecular weight and polydispersity index (PDI)>

After collecting 0.04 g of the prepared acrylic polymer, dissolving it in 10 g of tetrahydrofuran to prepare a sample sample, filtering the standard sample (polystyrene) and sample sample through a filter with a pore size of 0.45 μm, and then injecting into the GPC injector. did The number average molecular weight, weight average molecular weight and polydispersity of the acrylic polymer were measured by comparing the elution time of the sample sample with the calibration curve of the standard sample. Measurements were made using GPC (Infinity II 1260, Agilent Co.) at a flow rate of 1.00 mL/min and a column temperature of 35.0 °C.

Example 1 to 33

In an acrylic monomer composition in which 2-ethylhexyl acrylate, isobornyl acrylate and 2-hydroxyethyl acrylate were mixed in a weight ratio of 50:35:15 and 1 phr of benzophenone methacrylate based on 100 parts by weight of these, Table A silane-based chain transfer agent was mixed in the type and amount described in 1. The mixed composition was put into a reactor, nitrogen was introduced, the temperature was raised to 80 ° C, and polymerization was performed by adding 100 ppm of free radical thermal initiator V-70 (WAKO Co.) based on the total weight of the monomer composition.

In Table 1, TES means triethylsilane, DMPS means dimethylphenylsilane, TTMS means tris(trimethylsilyl)silane, PMDS means pentamethyldisilane, and TPS means triisopropylsilane.

TES
(phr) DMPS
(phr) TTMS
(phr) PMDS
(phr) TPS
(phr) M _w
(kDa) M _n
(kDa) P D I Example 1 0.05 749 173 4.3 Example 2 0.3 556 152 3.7 Example 3 One 289 107 2.7 Example 4 2 223 82 2.7 Example 5 3 124 43 2.9 Example 6 4 112 48 2.3 Example 7 5 92 42 2.2 Example 8 6 90 41 2.2 Example 9 0.05 647 184 3.5 Example 10 0.1 585 185 3.2 Example 11 0.3 449 155 2.9 Example 12 0.5 389 136 2.9 Example 13 One 269 104 2.6 Example 14 2 178 78 2.3 Example 15 3 145 68 2.1 Example 16 0.05 180 79 2.3 Example 17 0.1 118 54 2.2 Example 18 0.2 67 31 2.2 Example 19 0.3 46 22 2.1 Example 20 0.4 35 17 2.1 Example 21 0.5 26 13 2 Example 22 One 17 8 2.1 Example 23 0.05 426 131 3.3 Example 24 0.1 300 105 2.9 Example 25 0.3 181 79 2.3 Example 26 0.5 116 54 2.1 Example 27 One 66 32 2.1 Example 28 1.5 50 25 2 Example 29 2 38 19 2 Example 30 One 471 174 2.7 Example 31 2 270 99 2.7 Example 32 3 218 84 2.6 Example 33 4 183 77 2.4

comparative example 1 to 7

Acrylic polymers were prepared in the same composition and method as in Examples except for changing the type and content of the chain transfer agent according to the components and content ratios shown in Table 2 below.

In Table 2, n-DDM means n-dodecyl mercaptan, IOTG means isooctylthioglycolate, AMSD means 2,4-diphenyl-4-methyl-1-pentene, and DPE means diphenylethylene.

n-DDM
(phr) IOTG
(phr) AMSD
(phr) DPE
(phr) M _w
(kDa) M _n
(kDa) P D I note Comparative Example 1 One 30 13 2.3 Comparative Example 2 One 32 13 2.5 Comparative Example 3 One 230 52 4.4 Comparative Example 4 1.5 0.5 67 19 3.5 Comparative Example 5 One reaction does not proceed V-70
100 ppm Comparative Example 6 0.5 20 3.5 5.7 V-70
1,000 ppm Comparative Example 7 No chain transfer agent input 1,350 245 5.5

Conversion rates and the like of Examples and Comparative Examples were evaluated and shown in Table 2 below.

Referring to the results of Table 1-2, the acrylic polymer polymerized by the non-solvent free radical thermal polymerization method using a silane-based compound as a chain transfer agent according to the production method according to the present invention is an acrylic polymer polymerized using a conventional chain transfer agent. Consistent with, it can be confirmed that the molecular weight and polydispersity can be controlled so as not to become too large.

In Comparative Examples 1 and 2, molecular weight control was easy, but using a sulfur-containing chain transfer agent may cause problems such as corrosion of electrodes due to residual sulfur ions when applied to electronic products. In Comparative Examples 3 to 5, molecular weight control was not easy and polydispersity tended to be high because aromatic hydrocarbon-based chain transfer agents were used. In particular, when diphenylethylene was used, a problem occurred in that the initiation reaction did not proceed as the content increased. When using diphenylethylene according to Comparative Example 6, when the initiator content is increased, it is difficult to control the exothermic reaction, making it difficult to secure a stable polymerization process. When the chain transfer agent was not used according to Comparative Example 7, the acrylic polymer in the non-solvent thermal polymerization had an excessively high molecular weight of 1,000,000 or more.

Claims (11)

A method for producing an acrylic polymer by free radical thermal polymerization of a solvent-free acrylic monomer composition comprising a thermally polymerizable acrylic monomer, a free radical thermal initiator and a chain transfer agent,
The chain transfer agent is a silane-based chain transfer agent represented by Formula 1,
The acrylic polymer has a weight average molecular weight of 10,000 to 800,000 g/mol and a polydispersity of 1.5 to 5.0. Method for producing an acrylic polymer using solvent-free free radical thermal polymerization:
<Formula 1>

In Formula 1,
R ₁ , R ₂ and R ₃ are each independently a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, a hydroxyl group, an alkoxyl group, a silyl group, an amino group and a glycidyl group. According to claim 1,
The silane-based chain transfer agent of Formula 1 is at least one selected from the group consisting of triethylsilane, dimethylphenylsilane, tris(trimethylsilyl)silane, pentamethyldisilane and triisopropylsilane. A method for producing an acrylic polymer using polymerization. According to claim 1,
The method for producing an acrylic polymer using solvent-free free radical thermal polymerization, characterized in that the silane-based chain transfer agent of Formula 1 is at least one of triethylsilane and pentamethyldisilane. According to claim 1,
The content of the silane-based chain transfer agent of Formula 1 is 0.01 to 10 parts by weight based on 100 parts by weight of the thermally polymerizable acrylic monomer. According to claim 1,
The method for producing an acrylic polymer using solvent-free free radical thermal polymerization, characterized in that the thermally polymerizable acrylic monomer is a branched or unbranched (meth)acrylic acid having 1 to 20 carbon atoms or a derivative thereof. According to claim 5,
The thermally polymerizable acrylic monomer comprises at least two or more selected from the group consisting of alkyl (meth) acrylate, alicyclic (meth) acrylate, and hydroxy (meth) acrylate. Method for producing an acrylic polymer using. According to claim 1,
The method for producing an acrylic polymer using solvent-free free radical thermal polymerization, characterized in that the thermally polymerizable acrylic monomer comprises a thermally polymerizable acrylic monomer having a photoreactive group. According to claim 7,
The method for producing an acrylic polymer using non-solvent free radical thermal polymerization, characterized in that the photoreactive group is a benzophenone group. delete An acrylic polymer polymerized by the method of any one of claims 1 to 8. An acrylic adhesive composition comprising the acrylic polymer of claim 10.