KR20190053547A - Resin composition for automobile glazing - Google Patents

Abstract

The present invention relates to a resin composition comprising polymethylmethacrylate copolymers, which may be used for car glazing. The resin composition for car glazing according to the present invention has excellent impact resistance, weather resistance, scratch resistance, and abrasion resistance.

Description

[0001] Resin composition for automobile glazing {RESIN COMPOSITION FOR AUTOMOBILE GLAZING}

The present invention relates to a resin composition comprising a polymethyl methacrylate copolymer that can be used for automotive glazing.

In the automobile industry, weight reduction is a necessary task because of the reduction of carbon dioxide emission and the improvement of fuel efficiency.

On the other hand, the demand for the enlargement of the glass area such as the panoramic sunroof is increasing in the body for the design, the open feeling and the like.

Since the glass material applied to automobiles increases the weight of the vehicle body, studies are being actively conducted on technologies aiming to achieve weight reduction as a substitute material.

Among these materials, polycarbonate is one of the materials attracting attention because it has about half the weight of glass.

Polycarbonate is a thermoplastic resin having a thermal deformation temperature of 135 ° C or more, excellent in transparency, and excellent in impact resistance, dimensional stability, and heat resistance, and is widely used in automobiles as well as in electrical and electronic products. In recent years, it has been widely used as an automotive glazing material due to its excellent impact resistance and transparency.

However, polycarbonate is poor in scratch resistance and abrasion resistance, and has a low surface hardness, so that a high level hard coating is required. The hard coating process increases the cost and causes a decrease in productivity due to the addition of process steps.

On the other hand, use of an impact resistant polymethylmethacrylate resin having excellent surface hardness has been studied, but it is difficult to apply such a resin because haze is generated due to a change in refractive index depending on a temperature change.

Therefore, there is a need for research and development of a resin composition for automobile glazing which is superior in optical characteristics, such as being superior in surface hardness and impact resistance and capable of replacing a glass material to lighten a vehicle, and not causing haze according to temperature.

Korean Patent No. 10-1459130 (Oct. 31, 2014)

It is an object of the present invention to provide a resin composition for automobile glazing which maintains a high surface hardness and at the same time does not cause haze according to temperature change.

It is another object of the present invention to provide a resin composition for automobile glazing which is excellent in impact resistance and weather resistance.

Another object of the present invention is to provide a resin composition for automobile glazing which is excellent in scratch resistance and abrasion resistance.

It is another object of the present invention to provide a method for producing a polymethyl methacrylate copolymer having a low surface hardness and excellent ultraviolet stability, impact resistance and light transmittance, which is contained in the above resin composition for automotive glazing .

One embodiment of the present invention relates to a composition comprising a core consisting of a copolymer derived from 70 to 100% by weight of an acrylic acid ester monomer and 0 to 30% by weight of a methacrylic acid ester monomer, and a grafted on the core, wherein the methacrylic acid ester monomer is 50 to 99 And a shell composed of a copolymer derived from an acrylic acid ester monomer content of 1 to 50% by weight, based on the total weight of the resin composition for automobile glazing.

In the resin composition for automotive glazing according to an embodiment of the present invention, the polymethyl methacrylate copolymer may have 20 to 60% by weight of the core and 40 to 80% by weight of the shell.

In the resin composition for automotive glazing according to an embodiment of the present invention, the polymethyl methacrylate copolymer may have an average particle diameter of 50 to 150 nm.

The resin composition for automobile glazing according to an embodiment of the present invention may further comprise at least one additive selected from the group consisting of an antioxidant, a plasticizer, a releasing agent, a heat stabilizer, an antistatic agent, a flame retardant, a lubricant, an impact modifier, and a UV stabilizer .

Another aspect of the present invention may be a molded article made of the resin composition for automobile glazing described above.

Another aspect of the present invention is

(A) a core particle preparation step in which a solution containing at least one monomer selected from an acrylate ester monomer and a methacrylate ester monomer, an emulsifier, a grafting agent and an initiator is added to ion-exchanged water to effect emulsion polymerization, and

(B) preparing a shell layer for coating the particles by adding a methacrylate ester monomer, an acrylate monomer, a chain transfer agent and an initiator to a solution containing the particles produced by the emulsion polymerization,

To a process for producing a polymethyl methacrylate copolymer for automobile glazing.

In the method for preparing a polymethyl methacrylate copolymer according to an embodiment of the present invention, the monomer in the step (A) may contain 70 to 100% by weight of an acrylate monomer.

In the process for producing a polymethyl methacrylate copolymer according to an embodiment of the present invention, the methacrylic acid ester monomer is contained in an amount of 50 to 99% by weight and the acrylic acid ester monomer is contained in an amount of 1 to 50% by weight in the step (B) .

In the method for producing a polymethylmethacrylate copolymer according to an embodiment of the present invention, the step (B) is carried out by dividing the monomer into two or more stages when the monomer is added, and gradually decreases the content of the acrylic ester monomer And the like.

In the process for preparing a polymethyl methacrylate copolymer according to an embodiment of the present invention, the emulsifier may be any one or more anionic emulsifiers selected from alkaline alkyl phosphates and alkylsulfates having 4 to 30 carbon atoms.

In the process for preparing a polymethylmethacrylate copolymer according to an embodiment of the present invention, the grafting agent may be at least one selected from allyl (meth) acrylate and diallyl maleate.

The resin composition for automobile glazing according to the present invention has the advantage of maintaining high surface hardness and having no optical haze due to temperature change.

Unlike the polycarbonate resin, it has an advantage that hard coating is not required on a high level surface.

Further, the resin composition for automobile glazing of the present invention has an advantage of excellent impact resistance, weather resistance, scratch resistance and abrasion resistance.

Hereinafter, a resin composition for automobile glazing and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. The invention can be better understood by the following examples. The following examples are for illustrative purposes only and are not intended to limit the scope of protection defined by the appended claims. The technical terms and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs, unless otherwise defined.

In the present invention, the term " (meth) acrylate " means a combination of acrylate and methacrylate.

The inventors of the present invention have recognized that a polycarbonate resin used as a resin for automobile glazing has a low self-surface hardness and a high level of hard coating is required, thereby increasing cost and adding a process, As a result of deepening research on a material capable of replacing the resin, it has been found that by providing a polymethyl methacrylate copolymer having a core-shell structure, a high surface hardness can be realized and the refractive index change due to temperature change can be minimized, The present invention provides a resin composition for automobile glazing capable of realizing the characteristics of the present invention.

One aspect of the present invention is to provide a resin composition for automobile glazing comprising a polymethyl methacrylate copolymer having a core-shell multilayer structure. Specifically, the polymethyl methacrylate copolymer is a copolymer comprising a core composed of a copolymer derived from 70 to 100% by weight of an acrylate-based monomer and 0 to 30% by weight of a methacrylate-based monomer, , 50 to 99% by weight of a methacrylate ester monomer, and 1 to 50% by weight of an acrylate ester monomer. In this case, in the core made of the copolymer, the term " copolymer " has the meaning of a homopolymer composed of an acrylic ester monomer when the methacrylic ester monomer is 0% by weight. That is, the core particle may be composed of a homopolymer of an acrylate monomer or a copolymer of an acrylate monomer and a methacrylate ester monomer. The core particles preferably comprise 70 to 100% by weight of an acrylic ester monomer and 0 to 30% by weight of a methacrylic ester monomer, preferably 75 to 95% by weight of an acrylate ester monomer and 10 to 25% by weight of a methacrylate ester monomer When the above range is satisfied, it is effective in terms of realizing excellent impact resistance while having optical characteristics.

The shell layer is formed by grafting on the core particles. The shell layer comprises 50 to 99% by weight of a methacrylate ester monomer and 1 to 50% by weight of an acrylate ester monomer, and preferably 55 to 95% by weight of a methacrylate ester monomer, And 5 to 45% by weight of an acrylic ester monomer. When the above range is satisfied, it is effective in improving the surface properties of abrasion resistance, scratch resistance, impact resistance and weather resistance while maintaining a high surface hardness.

The present invention is characterized in that it does not contain an aromatic vinyl compound such as styrene which can be used to have a high refractive index. When an aromatic vinyl monomer such as styrene is used, the impact resistance and weather resistance are lowered. In particular, haze is generated according to temperature change, and optical properties are lowered, which makes it difficult to apply to an automobile glazing.

The acrylic ester monomer is an acrylic ester having 1 to 15 carbon atoms, preferably 2 to 8 carbon atoms. Specific examples thereof include ethyl acrylate, n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate And octyl acrylate, but is not limited thereto.

The methacrylic acid ester monomer is a methacrylic acid ester having 1 to 15 carbon atoms, preferably 2 to 8 carbon atoms, specifically methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, I- Butyl methacrylate, t-butyl methacrylate, lauryl methacrylate, and 2-ethylhexyl methacrylate, but is not limited thereto.

According to one embodiment of the present invention, the polymethyl methacrylate copolymer may be composed of 20 to 60% by weight of the core and 40 to 80% by weight of the shell. Preferably, the core may be composed of 25 to 55% by weight and the shell may be composed of 45 to 75% by weight. In the case of satisfying the above range, in view of realizing a high surface hardness and an impact strength characteristic, effective.

At this time, the core particles may have an average particle diameter of 5 to 50 nm and 10 to 40 nm. When the above-mentioned range is satisfied, it is effective in improving the impact resistance.

The polymethyl methacrylate copolymer may have an average particle diameter of 10 to 1,000 nm, specifically 20 to 500 nm, more specifically 50 to 200 nm. When the above-mentioned range is satisfied, it is more effective in terms of excellent optical characteristics at the same time as excellent surface characteristics and mechanical strength, but this is a non-limiting example and is not limited to the above numerical range.

The resin composition for automotive glazing according to one embodiment of the present invention may contain at least one additive selected from the group consisting of antioxidants, plasticizers, mold release agents, heat stabilizers, antistatic agents, flame retardants, lubricants, impact modifiers, But is not limited thereto.

Another aspect of the present invention is to provide a method for producing a polymethyl methacrylate copolymer.

A method for producing a polymethyl methacrylate copolymer according to an embodiment of the present invention comprises:

(A) a core particle preparation step in which a solution containing at least one monomer selected from an acrylate ester monomer and a methacrylate ester monomer, an emulsifier, a grafting agent and an initiator is added to ion-exchanged water to effect emulsion polymerization, and

(B) a step of preparing a shell layer in which a methacrylic acid ester monomer, an acrylic ester monomer, a chain transfer agent and an initiator are added to a solution containing particles produced by the emulsion polymerization and emulsion polymerization is carried out to coat the particles.

Specifically, the step (A) is a step of producing core particles of rubber. In the step of preparing the core particles, ion-exchanged water is put into a reactor under an inert gas atmosphere, and then an emulsifier is added to the reactor to sufficiently stir. In this case, the ion exchange water is preferably used in an amount of 100 to 500 parts by weight, specifically 200 to 400 parts by weight, based on 100 parts by weight of the total monomers, and the temperature range of the ion exchange water may be 50 to 70 ° C. When the above range is satisfied, it is effective for producing a copolymer having desired physical properties by emulsion polymerization.

Thereafter, a mixed solution obtained by mixing at least one monomer selected from an acrylate ester monomer and a methacrylate ester monomer with an emulsifier, a grafting agent and an initiator is emulsion-polymerized.

At this time, the acrylic acid ester monomer is contained in an amount of 70 to 100% by weight, preferably 75 to 95% by weight based on the total monomers, and when the above range is satisfied, it is effective in realizing excellent impact resistance without deteriorating other physical properties

The emulsifier is not particularly limited, but preferably at least one anionic emulsifier selected from the group consisting of alkaline alkyl phosphates having 4 to 30 carbon atoms, sodium dodecyl sulfate, sodium dodecylbenzenesulfate and alkylsulfate salts can be used have. At this time, the emulsifier may be added in an amount of 0.1 to 5 parts by weight, specifically 0.2 to 4 parts by weight based on 100 parts by weight of the total monomers.

The grafting agent may be at least one compound selected from the group consisting of allyl (meth) acrylate and diallyl maleate, but it is not limited thereto. It is not. The grafting agent may be contained in an amount of 0.1 to 10 parts by weight, specifically 0.5 to 5 parts by weight, based on 100 parts by weight of the total monomers. When the above range is satisfied, viscosity control is easy, polymerization stability can be ensured, and it is effective in terms of realizing mechanical strength such as tensile strength.

The initiator may be selected from the group consisting of ferrous sulfate, sodium ethylenediamine tetraacetate, cumene hydroperoxide, diisopropylbenzene hydroperoxide, azobisisobutylonitrile, tertiary butyl hydroperoxide, paramethanhydroperoxide and benzoyl peroxide Oxides, and the like, but the present invention is not limited thereto. At this time, the initiator may be included in an amount of 0.001 to 10 parts by weight, specifically 0.05 to 5 parts by weight, based on 100 parts by weight of the total monomers.

The core particle preparation step may further include a crosslinking agent. The crosslinking agent may be at least one selected from the group consisting of 1,2-ethanediol di (meth) acrylate, 1,3-propanediol di (meth) acrylate, 1,4-butanediol di (meth) Acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, divinylbenzene, ethylene glycol di (Meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di And the present invention is not limited thereto. The crosslinking agent may be included in an amount of 0 to 10 parts by weight, specifically 0.1 to 5 parts by weight, based on 100 parts by weight of the total monomers. When the range is satisfied, the crosslinking agent may be increased and more effective in improving physical properties. It is an example only and is not limited to the fraud level range.

The step (B) of preparing the shell layer is a step of forming an outer layer on the core particle surface prepared in the step (A).

Specifically, the outer layer is formed by adding a methacrylate ester monomer, an acrylate monomer, a chain transfer agent, and an initiator to the reaction solution containing the core particles prepared in the step (A) Thereby forming an outer layer.

At this time, when introducing the methacrylate ester monomer and the acrylic ester monomer into the reactor, it is preferable to divide at least two or more stages of the monomer mixture into the polymerized methacrylate copolymer It is more effective in terms of realizing surface characteristics and optical characteristics. In particular, it is preferable that the acrylic acid ester monomer is gradually added to the next stage from the initial stage. That is, it is preferable that at least two steps of the methacrylic ester monomer and 1 to 50% by weight of the acrylic acid ester monomer are added to the reactor, It is more preferable to inject them separately.

The chain transfer agent is capable of controlling the molecular weight of the polymethyl methacrylate copolymer, and may be selected from the group consisting of alkyl mercaptans having 2 to 18 carbon atoms, benzyl mercaptan, and mercapto acid. But is not limited thereto.

The step of preparing the shell layer may further include a crosslinking agent. The cross-linking agent may be the same as the cross-linking agent used in the core particle. The crosslinking agent may be included in an amount of 0 to 10 parts by weight, specifically 0.1 to 5 parts by weight, based on 100 parts by weight of the total monomers.

According to an embodiment of the present invention, when the polymerization reaction of the polymethyl methacrylate copolymer is completed after the step (B), a coagulation process may be performed using a coagulant. Thereafter, the polymethyl methacrylate copolymer may be separated and washed and dried. At this time, the flocculating agent is preferably an aqueous solution of an organic acid salt, and for example, at least one selected from the group consisting of sodium acetate, calcium acetate, sodium formate and calcium formate may be used. The flocculant may be contained in an amount of 0.01 to 5 parts by weight, preferably 0.5 to 4 parts by weight, based on the total suspension polymerization solution. Or by spray drying instead of agglomeration, washing and drying.

The present invention provides a molded article produced by using the above resin composition for automobile glazing.

The above-mentioned molded article can replace parts using glass material of automobile. Although the application field of the molded article is not limited to a great extent, it can be specifically applied to the fields of automobiles and electric and electronic products.

The molded article has a high surface hardness and a low haze even when the temperature changes, thereby realizing excellent optical characteristics and has an excellent impact resistance, abrasion resistance and scratch resistance.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples. In the following examples, the content indications are in parts by weight, and the parts by weight means the weights measured on the basis of one of the components. That is, based on 250 parts by weight of ion-exchanged water, the content of the remaining components is expressed as a ratio based on the weight of the ion-exchanged water.

(Example 1)

Preparation of polymethyl methacrylate copolymer

(A): 250 parts by weight of ion-exchanged water, 0.002 parts by weight of ferrous sulfate, 0.008 parts by weight of EDTA · 2Na salt, 0.2 parts by weight of sodium formaldehyde sulfoxylate and 2 parts by weight of sodium dodecyl sulfate were injected into a reactor equipped with a stirrer After nitrogen substitution, the temperature was raised to 65 占 폚. Thereafter, 1/10 of a mixed solution composed of 27 parts by weight of butyl acrylate, 3 parts by weight of methyl methacrylate, 1 part by weight of allyl methacrylate and 0.05 part by weight of tertiary butyl hydroperoxide was added dropwise for 30 minutes, 9/10 was added dropwise for 90 minutes and then stirred for 1 hour to effect emulsion polymerization. At this time, the average diameter of the obtained glassy polymer was 40 nm.

(B): Next, to the polymer obtained, 0.5 part by weight of sodium dodecyl sulfate, 6 parts by weight of butyl acrylate, 24 parts by weight of methyl methacrylate, 0.04 part by weight of octyl mercaptan, 0.05 part by weight of a mixed solution of 4 parts by weight of butyl acrylate, 36 parts by weight of methyl methacrylate, 0.12 part by weight of dodecyl mercaptan and 0.05 part by weight of tertiary butyl hydroperoxide was added dropwise over 1 hour. The mixture was added dropwise over 1 hour and polymerization reaction was carried out for 1 hour. The average diameter of the final polymer was 60 nm.

Step (C): 0.02 parts by weight of calcium acetate was added to 100 parts by weight of the solid particles to coagulate the polymethylmethacrylate copolymer, and the resultant particles were agglomerated at 70 DEG C, Followed by drying at 80 ° C.

The prepared polymethyl methacrylate copolymer was extruded using an extruder to prepare a specimen. The specimens were tested according to the following evaluation items, and the results are shown in Table 1 below.

(Example 2)

The procedure of Example 1 was repeated except that butyl acrylate and methyl methacrylate as monomers were not added in two stages but added all at once in step (B).

(Example 3)

The procedure of Example 1 was repeated except that the content of the polymethyl methacrylate copolymer was adjusted to 15% by weight of the core and 85% by weight of the shell.

(Example 4)

The procedure of Example 1 was repeated, except that the content of the polymethylmethacrylate copolymer core was 65 wt% and that of the shell was 35 wt%.

(Comparative Example 1)

The procedure of Example 1 was repeated except that 20 parts by weight of butyl acrylate, 8 parts by weight of methyl methacrylate and 2 parts by weight of allyl methacrylate were used as monomers in the step (A).

(Comparative Example 2)

(B), 40 parts by weight of butyl acrylate and 30 parts by weight of methyl methacrylate were used as monomers. 16 parts by weight of butylacrylate and 18 parts by weight of methyl methacrylate were added to the monomer, and 24 parts by weight of butyl acrylate and 12 parts by weight of methyl methacrylate were added to the monomer in the same manner as in Example 1, .

(Comparative Example 3)

Example 1 was carried out in the same manner as in Example 1, except that 5 parts by weight of a styrene monomer was further contained as a monomer in the step (A).

(Comparative Example 4)

Example 1 was carried out in the same manner as in Example 1, except that 5 parts by weight of a styrene monomer was further contained as a monomer in the step (B).

(evaluation)

(1) Transparency and haze: The haze was measured using a hazemeter in accordance with ASTM D1003. At this time, the temperature during the measurement was divided into 20 ° C and 70 ° C.

(2) Izod impact strength: Notched Izod impact strength was measured at room temperature in accordance with ASTM D256.

(3) Yellow Index: Measured according to ASTM D1925.

(4) Pencil hardness: Measured according to ASTM D3363.

[Table 1]

As shown in Table 1, Examples 1 to 4 according to the present invention have high transparency and extremely low haze despite temperature changes. In addition, it exhibited high yzod impact strength, low yellowness, high surface hardness, and excellent physical property balance. On the other hand, in Comparative Examples 1 and 2, the optical characteristics were largely lowered according to the range of the monomer constituting the core and the shell, and the impact strength and surface hardness characteristics were lower than those of the Examples. In Comparative Examples 3 and 4, the optical characteristics were remarkably lowered with temperature changes, and the surface strength and impact strength were also lowered. Thus, they were not suitable for use in automotive glazing Respectively.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the above description does not define the scope of the present invention, which is defined by the limitations of the following claims.

Claims (11)

A core comprising a copolymer derived from 70 to 100% by weight of an acrylic acid ester monomer and 0 to 30% by weight of a methacrylic acid ester monomer, and a core which is grafted onto the core, wherein 50 to 99% by weight of a methacrylic acid ester monomer, And a core shell structure composed of a shell made of a copolymer derived from 1 to 50% by weight of a polymethylmethacrylate copolymer. The method according to claim 1,
Wherein the polymethyl methacrylate copolymer has a core content of 20 to 60% by weight and a shell content of 40 to 80% by weight. The method according to claim 1,
Wherein the polymethyl methacrylate copolymer has an average particle size of 50 to 150 nm. The method according to claim 1,
Wherein the resin composition further comprises at least one additive selected from the group consisting of an antioxidant, a plasticizer, a releasing agent, a heat stabilizer, an antistatic agent, a flame retardant, a lubricant, an impact modifier, and a UV stabilizer. A molded article produced from the composition of any one of claims 1 to 4. (A) a core particle preparation step in which a solution in which ion exchange water is mixed with at least one monomer selected from an acrylate ester monomer and a methacrylate ester monomer, an emulsifier graft, and an initiator is added and emulsion polymerization is carried out; and
(B) preparing a shell layer for coating the particles by adding a methacrylate ester monomer, an acrylate monomer, a chain transfer agent and an initiator to a solution containing the particles produced by the emulsion polymerization,
Wherein the polyglycidyl methacrylate copolymer is a polyglycidyl methacrylate copolymer. The method according to claim 6,
Wherein the monomer comprises 70 to 100% by weight of an acrylate monomer in the step (A). The method according to claim 6,
Wherein the methacrylic acid ester monomer is contained in an amount of 50 to 99% by weight and the acrylic acid ester monomer is contained in an amount of 1 to 50% by weight in the step (B). The method according to claim 6,
Wherein the step (B) is carried out in two or more stages when the monomer is added, and the content of the acrylic acid ester monomer is further reduced to the next step. The method according to claim 6,
Wherein the emulsifier is at least one anionic emulsifier selected from alkaline alkyl phosphates and alkylsulfates having 4 to 30 carbon atoms. The method according to claim 6,
Wherein the grafting agent is at least one selected from allyl (meth) acrylate and diallyl maleate.