JPH0559266A - Polyester resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in strengths, especially low- temperature impact strength with minimized lowering in heat resistance, weathering resistance, rigidity, etc. CONSTITUTION:A reinforcing agent based on an acrylic graft polymer obtained by grafting 0-10 pts.wt. methacrylate-based grafting monomer and at least 0.05 pt.wt. grafting agent and/or crosslinking agent in the presence of 68-90 pts.wt. acrylic ester rubber prepared by using 0.1-0.9wt.% grafting agent and further grafting 10-32 pts.wt. methacrylate-based grafting monomer is used as a reinforcing agent for the title composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyester resin composition having good impact resistance. More specifically, the present invention relates to a polyester-based resin composition that is suitably used in fields where rigidity and strength, particularly low-temperature impact strength, are required, for example, production of automobile parts such as bumpers, spoilers, and side garnishes.

[0002]

2. Description of the Related Art Aromatic polyesters such as polybutylene terephthalate and polyethylene terephthalate are resins having good solvent resistance and moldability, but they are strong in strength, especially at low temperature impact strength. Not enough. Therefore, for the purpose of improving the strength, it has already been proposed to jointly use a reinforcing agent such as an MBS-based reinforcing agent, an ABS-based reinforcing agent, or an acrylic-based graft reinforcing agent.

However, MB using butadiene rubber
The use of S-based and ABS-based toughening agents has the problems that the thermal stability during processing deteriorates, molding coloring is likely to occur due to thermal deterioration, and weathering deterioration is likely to occur.

On the other hand, if the existing acrylic graft reinforcing agent is used, although the above-mentioned problems when using the MBS type reinforcing agent and the ABS type reinforcing agent are solved, there is a problem that the effect of improving the strength is low. However, in order to obtain the strength of the level required by the market, it is necessary to add a large amount of a reinforcing agent, and as a result, other physical properties such as rigidity are likely to be deteriorated, which is insufficient as a product. There is a problem that you can only get good things.

Therefore, it has been desired to develop an acrylic graft reinforcing agent which has a large strength improving effect even with a small amount of addition.

[0006]

It has been conventionally known that it is advantageous to increase the rubber content in the graft reinforcing agent as much as possible in order to obtain a graft reinforcing agent having good strength development. As a method of increasing the rubber content, if a conventionally known method, that is, a method of increasing the crosslinking degree of rubber is adopted, it is possible to obtain a graft product having a high rubber content even in the case of an acrylic graft reinforcing agent. However, in a system using a polyester resin as a matrix, a method of increasing the degree of cross-linking of the rubber portion to increase the rubber content gives only a low strength-developing ability, and it is not possible to obtain the intended reinforcing agent. It was found as a result of the study by the inventors. That is, in a system using a polyester resin as a matrix, it is important to set the degree of cross-linking of the rubber part to be low in terms of strength development. Since the amount of improvement in strength developing ability due to the increase in amount is offset by the amount of strength reduction resulting from increasing the degree of crosslinking of the rubber portion, good strength developing ability cannot be obtained. Therefore, in order to obtain an acrylic graft toughener whose strength development ability is significantly improved as compared with existing acrylic graft tougheners, it is necessary to use a rubber-based one having a low degree of crosslinking and a graft toughener having a large rubber content. Will be needed.
However, if the graft polymerization is simply carried out using a rubber having a low degree of crosslinking, it will not be possible to obtain a good powder form. In addition, the strength-developing power is low, contrary to expectations. The reason is probably that the graft monomer penetrates into the rubber layer and the graft layer is not sufficiently formed, so that the affinity between the reinforcing agent and the matrix resin is lowered, and only the strength developing ability is low. it is conceivable that. Therefore, as a result of intensive studies on the technique of increasing the amount of rubber while the degree of cross-linking of the rubber part remains low, the present inventors have set the amount of the grafting agent used in the rubber part to 0.1 to 0.9%. It was found to be significantly advantageous in strength over the range of common sense. Also, surprisingly, the cross-linking agent and / or the grafting agent used in the graft part is introduced only in the graft inner layer part rather than in the entire graft part (hereinafter also referred to as total cross-linking). It was found that that (hereinafter, also referred to as inner layer cross-linking) was significantly better in terms of strength.

That is, the amount of the grafting agent at the time of rubber polymerization is kept in a good amount for strength development, that is, kept small.
In the subsequent graft polymerization, by adopting the method of introducing a crosslinking agent and / or a grafting agent into the inner layer of the graft, it becomes possible to increase the rubber content in the graft strengthening agent, and to improve the strength development of the graft. You can get a toughening agent.

The introduction of the crosslinking agent and / or the grafting agent only in the graft inner layer portion (inner layer crosslinking) is stronger than the introduction of the crosslinking agent and / or the grafting agent in the entire graft portion (whole crosslinking). Although the reason why the expression is good is not clear, it is probably easier to make the outer layer of the graft layer to be a layer which does not use the crosslinking agent and / or the grafting agent because the molecular entanglement with the matrix resin is easier. It is considered that this is because the affinity is further improved and the strength developing ability is increased.

Further, as described above, it is advantageous to use a grafting agent as a crosslinking agent for the rubber portion.

The present invention has been made from the above viewpoint, and has developed an acrylic graft strengthening agent whose impact strength is significantly improved with a small addition amount, and the acrylic graft strengthening agent is used as a polyester. By adding to the system resin, the embrittlement temperature is low, was made for the purpose of obtaining a polyester resin composition having excellent low temperature impact strength, (A) 65-95 parts polyester (parts by weight, The same shall apply hereinafter) and (B) Grafting agent 0.1 to 0.9% (% by weight, the same applies hereinafter)
Graft monomer consisting of 60 to 100% of a methacrylic ester and 40 to 0% of a vinyl monomer copolymerizable therewith in the presence of 68 to 90 parts of an acrylic ester rubber (hereinafter also referred to as rubber) 0 to 10 parts and a grafting agent and / or a cross-linking agent of 0.05 parts or more (hereinafter, also referred to as a graft component) are graft-polymerized, and further, 60 to 100% of a methacrylic acid ester and 40 to 0 of a copolymerizable vinyl monomer are used. Acrylic graft strengthening agent obtained by graft polymerization of 10 to 32 parts of graft monomer (hereinafter, also referred to as graft component) consisting of
It relates to a polyester resin composition comprising 5 parts.

[0011]

Actions and Examples As the polyester used in the present invention, any polyester which is generally used for molding can be used without particular limitation. Specific examples of such polyesters include aromatic polyesters such as polybutylene terephthalate and polyethylene terephthalate.

The acrylic graft reinforcing agent used in the present invention eliminates the disadvantage of the conventional acrylic graft reinforcing agent that the effect of improving the strength is low, and improves the impact strength significantly by adding a small amount. It is obtained by graft-polymerizing a graft component in the presence of rubber and then graft-polymerizing the graft component.

The rubber-based grafting agent 0.1 to 0.9
%, The acrylic ester rubber is a component for imparting impact strength, especially strength at low temperature.

The rubber is prepared by using 0.1 to 0.9% of one or more grafting agents as described above, preferably 0.1 to 0.7%, and more preferably 0.1 to 0.7%.
0.2 to 0.7% is used, 50% or more of acrylic acid ester units as constituents, and 70 to 100%
% Rubber is preferred. The ratio of grafting agent is 0.1
If it is less than%, the obtained graft product becomes crumb-like when solidified, and it becomes difficult to obtain a stable and clean powder. Further, if it exceeds 0.9%, the strength-developing ability decreases. If the acrylic acid ester unit content is less than 50%, it will not function as an acrylic rubber.

The above-mentioned grafting agent means in the molecular structure
It is a compound containing two or more different polymerization-reactive groups, and is for crosslinking the rubber part and providing a graft active site during the graft polymerization. The reason why the grafting agent is used for crosslinking the rubber part is as follows.

The strength development ability of the graft reinforcing agent has an optimum point in a region where the degree of crosslinking of the rubber portion is relatively low. That is,
The cross-linking agent or the grafting agent used during the polymerization of the rubber part is limited to an amount sufficient to prevent the graft monomer from excessively penetrating into the rubber part during the graft polymerization,
Moreover, it is important that even a relatively small amount thereof can sufficiently act as a source of graft active sites during graft polymerization. From this point of view, using a compound containing a plurality of groups having the same polymerization reactivity for crosslinking the rubber part (crosslinking agent used in the present invention), compared with the contribution to rubber crosslinking, Since the degree of provision of graft active points becomes low and the balance between the above-mentioned two effects is lost,
It is not preferable as compared with the use of a compound containing two or more different polymerization reactive groups (grafting agent used in the present invention).

Specific examples of the grafting agent include allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate and monoallyl fumarate. However, allyl methacrylate and diallyl maleate are preferable because they are easily available and are advantageous in terms of cost.

Specific examples of other constituents that can be used together with the acrylic acid ester unit include diene monomers such as butadiene and isoprene, aromatic vinyl monomers, and methacrylic acid ester monomers.

The average particle size of the rubber is usually 1500-3500
It is about A, and the amount of the toluene insoluble component is usually about 75 to 98%.

Examples of the rubber include butyl acrylate rubber, n-octyl acrylate rubber, 2-ethyl-hexyl acrylate rubber, and butyl acrylate / butadiene copolymer containing 50% or more of acrylic acid ester. Examples thereof include a copolymer rubber composed of an acrylic ester and a diene monomer, and an acrylic ester / silicone copolymer rubber containing 50% or more of an acrylic ester.

The above-mentioned graft component is a component composed of a grafting agent and / or a cross-linking agent and, if necessary, a graft monomer as mentioned above, and the graft compound to be subsequently polymerized is more easily grafted. The grafting monomer used for the above purpose and, if necessary, used is used in a minor range depending on the purpose.

The grafting agent is also a compound containing two or more different polymerizable groups in its molecular structure, like the grafting agent used for the rubber.

Specific examples of the grafting agent include allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate and monoallyl fumarate. It is preferable to use a mixture of one or two selected from maleates, not only in terms of physical properties, but also because they are easily available and cost effective.

The cross-linking agent is a compound containing a plurality of the same polymerization-reactive groups. Specific examples of the cross-linking agent include, for example, divinylbenzene, diallyl phthalate,
Butylenediacrylate, butylenedimethacrylate, etc. are mentioned.

The above-mentioned grafting agent and cross-linking agent may be used alone or in combination, but it is preferable to use only the grafting agent without using the cross-linking agent. Is preferable because it is more likely to undergo graft polymerization. That is, the grafting component is easily grafted with a smaller amount than when only the crosslinking agent is used.

The above-mentioned graft monomer optionally used (hereinafter, also referred to as graft inner layer monomer) comprises 60 to 100% of methacrylic acid ester and 40 to 0% of vinyl monomer copolymerizable therewith. When the proportion of the methacrylic acid ester is less than 60%, that is, when the copolymerizable vinyl monomer exceeds 40%, the characteristics of using the methacrylic acid ester are lost, for example, the weather resistance is deteriorated.

Specific examples of the methacrylic acid ester include methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate. Further, specific examples of vinyl monomers copolymerizable with these methacrylic acid esters include, for example, acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, styrene, α-methylstyrene, chlorostyrene, and the like. Examples thereof include vinyl vinyl monomers such as aromatic vinyl monomers, acrylonitrile and methacrylonitrile, and vinyl halides such as vinyl chloride and vinyl bromide.

The graft monomer as the graft component (hereinafter, also referred to as the graft outer layer monomer) is a component for improving the affinity of the acrylic graft reinforcing agent for the matrix resin polyester.

The graft component comprises 60 to 100% of methacrylic acid ester, preferably 80 to 100%, and 40 to 0% of vinyl monomer copolymerizable therewith, preferably 20%.
Consists of ~ 0. When the ratio of the methacrylic acid ester is less than 60%, that is, when the copolymerizable vinyl monomer exceeds 40%, the characteristics of the methacrylic acid ester are lost.

Specific examples of the methacrylic acid ester include methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like, and specific examples of the vinyl-based monomer copolymerizable therewith. , Alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, aromatic vinyl monomers such as styrene, α-methylstyrene, chlorostyrene, vinyl cyan monomers such as acrylonitrile and methacrylonitrile, vinyl chloride , Vinyl halides such as vinyl bromide, and the like.

The acrylic graft reinforcing agent used in the present invention comprises 0.05 part of a grafting agent and / or a crosslinking agent as the grafting component in the presence of 68 to 90 parts, preferably 70 to 85 parts of the rubber. As described above, preferably 0.05 to 5 parts and 0 to 10 parts, preferably 3 to 10 parts of the graft inner layer monomer are graft-polymerized, and further the graft component is added.
It is obtained by graft polymerization of 10 to 32 parts, preferably 15 to 30 parts.

When the amount of the rubber used is less than 68 parts, the function as a reinforcing agent becomes insufficient due to the small amount of rubber,
If it exceeds the area, it will be difficult to form the graft layer,
Strengthening ability is also reduced. If the amount of the cross-linking agent and / or the grafting agent used is less than 0.05 part, it becomes difficult to graft the graft component. Further, if it exceeds 5 parts, the graft layer becomes hard and the reinforcing ability tends to decrease. When the amount of the graft inner layer monomer used exceeds 10 parts, the amount of the grafting agent also increases accordingly, the graft layer is hardened, and the strengthening ability is lowered. When the amount of the graft component used is less than 10 parts, it is difficult to form the graft layer, and the function as the graft layer is deteriorated.

Further, from the viewpoint that the molecular entanglement with the matrix resin becomes easier, the ratio of the graft inner layer monomer used is less than half of the total weight of the graft inner layer monomer and the graft outer layer monomer. Preferably, the graft portion of the outer layer formed by polymerization of the graft outer layer monomer (hereinafter referred to as the graft outer layer portion) is preferably a layer that does not use a crosslinking agent or a grafting agent.

The above-mentioned graft polymerization method is not particularly limited except that the crosslinking agent and / or the grafting agent is introduced into only the graft inner layer portion, but it is the simplest graft polymerization formulation. For example, a two-step grafting method in which a cross-linking agent and / or a grafting agent and a small amount of a grafting monomer are used in the first step and no cross-linking agent or a grafting agent is used in the second step but only the grafting monomer is grafted It may be adopted, or the graft polymerization may be further divided to proceed. The graft polymerization is preferably an emulsion polymerization method because continuous addition is easy. The emulsion polymerization initiator system is not particularly limited, and for example, an emulsion polymerization method using a redox polymerization initiator can be adopted.

As the redox-based polymerization initiator, known redox-based initiators can be used, for example, organic peroxide / (ferrous sulfate, sodium formaldehyde sulfoxylate, ethylenediamine acetate salt) -based, organic Examples thereof include peroxide / (ferrous sulfate, glucose, sodium pyrolylate) system and organic peroxide / (ferrous sulfate, dextrose, sodium pyrolylate) system.

The resin composition of the present invention contains 5 to 35 parts, preferably 15 parts of the acrylic graft reinforcing agent so that the total amount of the polyester and the acrylic graft reinforcing agent is 100 parts.
-30 parts and 65-95 parts of polyester, preferably 85-70 parts are blended. If the compounding amount of the acrylic graft reinforcing agent is less than 5 parts, the strength is not sufficiently expressed, and if it exceeds 35 parts, the decrease in rigidity due to the decrease in elastic modulus becomes remarkable.

There is no particular limitation on the method of blending the above-mentioned polyester, which is a matrix resin, and the acrylic graft reinforcing agent, and a known method can be used.

The resin composition of the present invention has good low temperature strength because the acrylic graft reinforcing agent is used as a reinforcing agent for polyester. That is, for example, the low temperature limit temperature (brittleness temperature) of ductile fracture of the obtained molded product is low, as compared with the case where a commercially available acrylic graft reinforcing agent is mixed in the same amount. Further, since the acrylic graft strengthening agent can obtain an effective strength developing effect with a small amount of additive, adverse effects on other physical properties due to excessive addition of the reinforcing agent are suppressed as much as possible.

Next, the resin composition of the present invention will be described with reference to examples, but these are all examples.
It does not limit the content of the present invention.

Example 1 (i) Manufacture of a rubber-like polymer The components shown in Table 1 were kept at a temperature of 40 ° C. in a nitrogen stream, and the monomer and cumene hydroperoxide ( (Hereinafter referred to as CHP)
An amount corresponding to 7 parts of n-butyl acrylate was charged all at once, and polymerization was carried out for 1.5 hours. Then, the remaining amount of the mixed solution, that is, the amount corresponding to 73 parts of n-butyl acrylate is 5.
Added over 5 hours. During this time, 1 part of sodium oleate was continuously added.

[0041]

[Table 1]

[0042]

[Table 2]

2.5 hours after the addition of the monomer is completed, 40 ° C.
To complete the polymerization. The polymerization conversion rate was 95%.
The average particle size at the end of the polymerization was 2200 A (measured by utilizing light scattering at a wavelength of 546 μm), and the amount of the toluene-insoluble component in the rubber was 85%.

(Ii) Preparation of Graft Reinforcing Agent The aqueous dispersion of the rubber-like polymer obtained in (i) above was heated to 50 ° C. in a nitrogen stream, and then the components shown in Table 3 were added over 30 minutes. And then held for 45 minutes.

[0045]

[Table 3]

After the components shown in Table 4 were added over 1.25 hours, 0.02 part of CHP was added and post-polymerization was carried out for 2 hours to complete the polymerization. The polymerization conversion rate was 95%.

[0047]

[Table 4]

The obtained latex is coagulated by a usual method,
After heat treatment and drying, a white powdery sample was obtained.

(Iii) Production of resin composition Next, polybutylene terephthalate (manufactured by Toray Industries, Inc.,
# 1401) 75 parts, and 25 parts of the graft strengthener obtained as an impact resistance improver, phosphorus stabilizer (Nissan Ferro Co., Ltd.)
Made, Ferro-904) 0.2 part vented twin screw extruder (44m /
m, L / D = 28, TEX-44-ss, manufactured by Nippon Steel Co., Ltd., and extruded and kneaded under the condition that the resin temperature was about 265 ° C. After drying the obtained pellets at 120 ℃ for 2 hours,
A sample for physical property evaluation was obtained by injection molding.

According to JIS K 7110, as a criterion for determining the impact strength of the obtained sample, 1/8 with V-notch
The Izod value was measured at a measurement temperature shown in Table 5 using an inch bar. The results are shown in Table 5.

Examples 2 to 3 and Comparative Examples 1 to 2 The amounts of ALMA shown in Table 2 were 0.2 parts, 0.6 parts and 1.
Samples were prepared in the same manner as in Example 1 except that the amount was 0 parts and 1.5 parts, and the characteristics were evaluated. The results are shown in Table 5.

Example 4 A sample was prepared in the same manner as in Example 1 except that diallyl maleate was used instead of ALMA shown in Table 2, and the characteristics were evaluated. The results are shown in Table 5.

Example 5 Except that the amount of n-butyl acrylate shown in Table 2 was 85 parts, the MMA of Table 4 was 10 parts, and the other components shown in Table 2 or Table 4 were proportioned accordingly. A sample was prepared in the same manner as in Example 1 and its characteristics were evaluated. The results are shown in Table 5.

Comparative Example 3 A sample was prepared in the same manner as in Example 1 except that ALMA was not used when the components shown in Table 3 were added and polymerized. I couldn't do it.

Comparative Example 4 70 parts of n-butyl acrylate and 1.4 parts of ALMA shown in Table 2 were used, and MMA of Table 4 was changed to 25 parts, and other components shown in Table 2 or Table 4 were proportionately distributed. The sample was prepared according to the method of Example 1, and the characteristics were evaluated. The results are shown in Table 5.

Comparative Example 5 A sample was prepared in the same manner as in Example 4 except that 1.5 parts of diallyl maleate was used, and the characteristics were evaluated. The results are shown in Table 5.

Comparative Example 6 A sample was prepared in the same manner as in Example 1 except that the components shown in Tables 3 and 4 were mixed and ALMA was dispersed in all the grafting monomers to carry out polymerization. Was evaluated. The results are shown in Table 5.

Comparative Example 7 A sample was prepared in the same manner as in Example 1 except that butylenediacrylate was used instead of ALMA shown in Table 2, and the characteristics were evaluated. The results are shown in Table 5.

[0059]

[Table 5]

[0060]

The polyester resin composition of the present invention is
A resin composition in which heat resistance, weather resistance, rigidity, etc. are not significantly reduced and a strength, especially a low temperature impact strength is greatly improved by adding a small amount of a specific acrylic graft reinforcing agent.

Claims (4)

[Claims] 1. A methacrylic acid ester of 60 to 90 parts by weight in the presence of (A) 65 to 95 parts by weight of polyester and (B) 0.1 to 0.9% by weight of a grafting agent and 68 to 90 parts by weight of an acrylate rubber. Graft-polymerized 0 to 10 parts by weight of a grafting monomer consisting of 100% by weight and 40 to 0% by weight of a vinyl-based monomer copolymerizable therewith, and 0.05 or more parts by weight of a grafting agent and / or a cross-linking agent. Containing 35 to 5 parts by weight of an acrylic graft reinforcing agent obtained by graft polymerizing 10 to 32 parts by weight of a grafting monomer consisting of 60 to 100% by weight of an ester and 40 to 0% by weight of a vinylic monomer copolymerizable therewith. A polyester-based resin composition comprising: 2. The composition according to claim 1, wherein the acrylic acid ester rubber is a rubber containing 0.1 to 0.7% by weight of a grafting agent. 3. One or two grafting agents are used without polymerizing the grafting agent and / or the crosslinking agent in the presence of 68 to 90 parts by weight of the acrylic ester rubber. The composition according to claim 1, wherein the above is used. 4. The composition according to claim 1, wherein the grafting agent comprises one kind or a mixture of two kinds selected from allyl methacrylate and diallyl maleate.