JPH0228251A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition suitable for exterior automotive trim use by incorporating an ionomer resin graft copolymerized with polyamide oligomer with a benzotriazole-based ultraviolet light absorber and hindered amine-based light stabilizer. CONSTITUTION:The objective resin composition can be obtained by incorporating (A) 100 pts.wt. of a graft copolymer produced by graft copolymerization of 30-3wt.% of a polyamide oligomer (pref. caprolactam oligomer 6-35 in number- average polymerization degree) to 70-97wt.% of a zinc ion-crosslinked product (pref. 5-90% in neutralization degree) from ethylene-alpha,beta-unsaturated carboxylic acid copolymer with (B) 0.1-1 pt.wt. of a ultraviolet light absorber comprising a hydrophenyl-substituted benzotriazole compound and (C) 0.1-1 pt.wt. of a hindered amine-based light stabilizer, and pref. furthermore, (D) each 0.01-1 pt.wt. of a hindered phenol compound-based stabilizer and/or phosphorus compound-based stabilizer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to resin compositions with improved weather resistance. More specifically, the present invention relates to a graft copolymerized ionomer resin composition having excellent weather resistance and particularly suitable for automotive exterior applications.

Conventional technology Ionomer resin, which is a metal ion crosslinked product of ethylene-α, β-unsaturated carboxylic acid copolymer, has hydrogen bonds and metal ion bonds in its molecules, so it has excellent processability, transparency, strength, It has impact resistance and abrasion resistance, and is used in a wide range of applications.

Furthermore, in order to improve the rigidity of the ionomer, the applicant of the present invention has developed a graft copolymer in which a polyamide oligomer is graft copolymerized onto a zinc ion crosslinked product of an ethylene-α,β-unsaturated carboxylic acid copolymer. (hereinafter referred to as a graft copolymer) (Japanese Unexamined Patent Publication No. 59-157122), the thick-walled molded product made of the graft copolymer has only improved rigidity. First, it has excellent wax remover resistance (kerosene is used to wash and remove the anti-rust guard wax painted on new cars; its appearance does not change even when washed with hot water), which is an important physical property for automotive exterior parts. Moreover, impact resistance
Since it maintains scratch resistance, it is expected to be used as automotive exterior parts.

However, automotive exterior parts must withstand harsh outdoor exposure for long periods of time, and in order to use this graft copolymer as an automotive exterior part, its weather resistance is not yet sufficient, and the weather resistance is limited to 63°C. In the accelerated weathering test using a Sunshine Weatherometer, there was a drawback that cracks appeared within 2000 hours. As a result of considering improvements by adding additives, we found that a graft copolymer with sufficient weather resistance as a material for automobile exterior parts can be obtained by combining a specific ultraviolet absorber and a light stabilizer. I discovered that.

That is, the present invention provides a graft copolymer obtained by graft copolymerizing about 30 to 3% by weight of a polyamide oligomer to about 70 to 97% by weight of a zinc ion crosslinked product of an ethylene-α,β-unsaturated carboxylic acid copolymer. The present invention relates to a resin composition with improved weather resistance, which is obtained by adding a benzotriazole ultraviolet absorber and a hindered amine light stabilizer to the combination.

There are many known UV absorbers to be added to resins, such as benzophenone, salicylate, benzotriazole, cyanoacrylate, and oxalic acid anilide. Addition of an ultraviolet absorber to a graft copolymer obtained by graft copolymerizing the There are some things that cannot be achieved. For example, 2-hydroxy-4-n-
Octoxybenzophenone and 12-hydroxy-4-n
- When a benzophenone compound such as octadecyloxybenzophenone is added to the graft copolymer, the benzophenone compound and the polyamide oligomer react and the graft copolymer is colored bright yellow. Also, ethyl-2-
When a cyanoacrylate compound such as cyano-3,5-diphenylacrylate is added, the graft copolymer molded product becomes cloudy and its transparency is significantly impaired. When an oxalic acid anilide compound such as 2-ethoxy-2'-ethyl oxalic acid bisanilide is added to the graft copolymer, it has the disadvantage that it bleeds out during aging, resulting in white turbidity and loss of transparency.

However, unlike the other UV absorbers mentioned above, benzotriazole-based UV absorbers do not exhibit any coloring or clouding phenomena within the range of addition amount sufficient to exhibit the effect of improving weather resistance. It was discovered that the copolymer is excellent as an ultraviolet absorber.

In this way, benzotriazole-based UV absorbers exhibit far superior weather resistance improvement effects compared to other UV absorbers, but even so, graft copolymer compositions containing only benzotriazole-based UV absorbers When exposed outdoors for a long period of time, cracks were observed to occur.The present inventors investigated the formulation of additives to prevent the occurrence of cracks, and found that a hindered amine-based light-resistant stabilizer. It has been found that by using the agent in combination with a benzotriazole-based ultraviolet absorber, a graft copolymer that does not develop cracks even after long-term exposure and has excellent weather resistance can be obtained.

In other words, improvement in the weather resistance of the graft copolymer obtained by graft copolymerizing an ionomer with a polyamide oligomer was achieved only by using a specific ultraviolet absorber and in combination with a specific light stabilizer. It is.

The benzotriazole-based ultraviolet absorber used in the resin composition of the present invention to solve the above problems is a hydroxyphenyl-substituted benzotriazole compound having the following basic structure. 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole 2-(3,5-dyl-t-butyl -2-hydroxyphenyl)-5-chlorobenzotriazole, 2-
(3,5-di-t-7mil-2-hydroxyphenyl)
Benzotriazole, 2-(3,5-di-t-butyl-
2-hydroxyphenyl)benzotriazole, 2-(
5-methyl-2-hydroquinphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α
-dimethylbenzyl)phenyl]-2) Benzotriazole compounds such as 1-penztriazole can be mentioned.

In addition, as the hindered amine light stabilizer used in the present invention, compounds having a piperidine structure in which the 2 and 6 positions are all substituted with alkyl are particularly suitable, and specifically, bis(2,2,6,6- Tetramethyl-4-piperidyl) sebacate, bis(1,2,2,8,6-pentamethyl-4-piperidyl) sebacate, dimethyl-1-(2-hydroxyethyl)-4-hydroxy-succinate
Examples include 2,2,6,6-titramethylpiperidine polycondensate.

The amount of the benzotriazole UV absorber added to the graft copolymer is preferably 0.1 to 1 part by weight per 100 parts by weight of the graft copolymer. The graft copolymer tends to turn yellow and additives tend to bleed out.

Furthermore, if the amount added is small, it is difficult to obtain a sufficient effect of improving weather resistance.

The preferred amount of the hindered amine light stabilizer is 0.1
Part by weight to 1 part by weight. If the amount added is too large, the graft copolymer may become cloudy or the hindered amine light stabilizer may bleed out. Furthermore, if the amount added is too small, the effect of improving weather resistance will be insufficient.

In the present invention, the ethylene-α, β-unsaturated carboxylic acid copolymer that serves as the base polymer of the ionomer is a copolymer of ethylene and α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid. Although a combination is used, if necessary, other α-olefins, α, β-unsaturated carboxylic acid esters, vinyl esters, etc. can be copolymerized to form a multi-component copolymer.

Specifically, ethylene-acrylic acid (or methacrylic acid) copolymer, ethylene-acrylic acid ester (or methacrylic acid ester)-acrylic acid (or methacrylic acid) copolymer, ethylene-preic anhydride copolymer,
Examples include ethylene-maleic anhydride-acetic acid g-vinyl 1i combination, ethylene-maleic acid monoester cofi combination, ethylene-maleic acid monoester-acrylic ester (or methacrylic ester) copolymer, and the like.

The content of α, β unsaturated carboxylic acid in the copolymer is approximately 3
The content is preferably 3% by weight, preferably ~25% by weight
In the case of non-vortexing, the graft copolymerization reaction with the polyamide oligomer is difficult to proceed, and the wax remover resistance is not sufficiently improved. Moreover, if the content exceeds 25% by weight, the melting point of the graft copolymer will be low, causing problems in terms of practical use of molded products.

The ethylene-α,β unsaturated carboxylic acid copolymer is crosslinked with zinc ions to produce an ionomer, and the degree of neutralization is preferably in the range of about 5 to 90%. In addition, the graft copolymerization reaction between the ionomer and the polyamide oligomer is accompanied by the formation of ionic bonds, and it is thought that an amine complex ion is formed between the zinc ion in the ionomer and the primary amine group at the end of the polyamide oligomer. . In the present invention, an ionomer crosslinked with zinc ions is used, but it may contain other metal ions as long as it is equivalent to or less than zinc.In addition, in a graft copolymerization reaction with a polyamide oligomer, Other ionomers may also be present in the range in which the amount of metal ions is equal to or less than that of zinc.

The polyamide oligomer to be graft copolymerized with the ionomer has a primary amino group at one end, and the other end is blocked with, for example, an N-fulkylamide group having 1 to 20 carbon atoms.

Such polyamide oligomers are lactam or ω-
It is obtained by polymerizing a lit aminocarboxylic acid and using an N-alkylamine as a terminal blocking agent. The most preferred polyamide oligomers for the present invention are caprolactam oligomers having a number average degree of polymerization of 6 to 35. If the number average degree of polymerization is less than 6, there is no substantial stiffness improvement effect,
When a polyamide oligomer with a uniformly dispersed average degree of polymerization exceeding 35 is used, the reaction rate of the graft copolymer becomes slow,
Graft copolymers are difficult to produce.

Although the graft copolymer differs depending on the type of ionomer, the ionomer content is 70 to 97% by weight, preferably 8% by weight.
0 to 97% by weight, polyamide oligomer 30 to 3
It is obtained by graft copolymerizing % by weight, preferably 20 to 3% by weight. If the amount of polyamide oligomer used is too large, the polyamide oligomer may remain unreacted depending on the type of ionomer, and the viscosity of the graft copolymer mixture may decrease or pelletization may become extremely difficult. On the other hand, if the proportion of polyamide oligomer is less than this, the improvement in heat resistance and wax removability, which is important as a material for automobile exterior parts, will be insufficient.

The graft copolymerization reaction is carried out at a temperature above the melting point of the ionomer, preferably about 150 to 250°C, by kneading it with a polyamide oligomer, usually using a melt kneading device such as a screw extruder.

Although the graft copolymer itself can be used as a resin composition, it can also be used in a blend with other thermoplastic resins, such as ethylene-α, β-unsaturated carboxylic acid ester copolymers. It is. In this case, blending may be performed at any stage before or after the graft copolymerization reaction.

The resin composition of the present invention has significantly improved weather resistance due to the combined use of a benzotriazole ultraviolet absorber and a hindered amine light stabilizer. Adding a phosphorus compound stabilizer further improves heat resistance and oxidation resistance, resulting in a resin composition with even better weather resistance, making it suitable for applications used outdoors under harsh conditions, such as automotive exterior parts. It is suitable for These stabilizers can be blended, for example, in an amount of 0.01 to 1 part by weight per 100 parts by weight of the graft copolymer.

Hindered phenol compound stabilizers have 2,6
Substituted preferably a compound having a 2,6 alkyl substituted phenol structure, specifically octadecyl-3-(3
, 5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythrityl-tetrakis-[3-
(3,5-di-t-butyl-4-hydroxyphenyl)propionate 1 and the like can be mentioned.

As the phosphorus compound stabilizer, organic phosphate esters or organic phosphite esters are suitable. Specifically, phosphorus compounds such as trisoctyl phosphite, distea, lylbentaerythritol diphosphite, and tricresyl phosphate are suitable. I can give it to you.

The resin composition of the present invention also includes pigments, antistatic IF, agents,
Other additives may also be added.

The ultraviolet absorber, light stabilizer, and other additives used in the present invention may be added to the graft copolymer after the graft copolymer is formed. The ionomer and the polyamide oligomer may be added to either or both of them at a temperature higher than the melting point of the oligomer, preferably about 150°C to 250°C, using a crosstalk device such as an extruder. It can also be added at the same time.

Effects of the Invention Since the thus obtained G-Latt copolymer assembly has excellent weather resistance, it can be manufactured into bumper moldings and windshield moldings using molding methods such as injection molding, extrusion sector molding, and profile extrusion molding. 1. For use as a transparent surface layer or a glossy colored surface layer, especially for automotive exterior parts, such as side protectors, etc. T can. In addition to automotive exterior parts, it can also be used outside the layer, such as ski boots, other sports equipment, and civil engineering and construction products that require weather resistance.

The present invention will be explained below with reference to Examples.

Ethylene-methacrylic acid copolymer (methacrylic acid content: 1
5%) zinc ion crosslinked product (ionization degree 50%), 10 parts by weight ε-caprolactam oligomer (number average degree of polymerization 20, melting point 213°C, terminal carboxyl group blocked with n-hexylamine), ultraviolet rays. As an absorbent2
-(3,5-di-t-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, (Tinuvin 327 manufactured by Ciba Geigy), 5 parts by weight and bis(2,2,6,6- Tetramethyl-4-piperidyl) sebacate (Nol LS770 manufactured by Ciba Geigy) 0
．． After tri-blending 5 parts by weight, 2 with T-die
It was supplied to a axial extruder a (screw diameter 30 mm, L/D=25) and extruded at a resin temperature of about 220° C. to obtain a sheet with a thickness of about 1 mm. The obtained sheet was subjected to an accelerated weather resistance test using a carbon arc type (% type) (12 minutes out of 60 minutes), and changes in appearance such as the hue of the sheet and the presence or absence of cracks were examined. As a result, the above sheet had no abnormality in appearance even after the 2000 hour weather test and was colorless and transparent.

Yorakueni J A sheet was prepared in the same manner as in Example 1 except that the ultraviolet absorber and light stabilizer listed in Table 1 were used, and the weather resistance was evaluated. As a result, the sheets of Comparative Examples 1 and 3 to which no ultraviolet absorber was added were colored yellow after 500 hours. In addition, in Comparative Example 2 in which only Tinuvin 328 was added as an ultraviolet absorber, 2
A crack appeared after 000 hours. In Comparative Examples 4 to 6 in which ultraviolet absorbers other than benzotriazole-based ultraviolet absorbers were used, the sheets were colored yellow or became cloudy, and the colorless and transparent characteristics of the graft copolymers were impaired.

Zinc ion crosslinked product (ionization degree 60%) of methacrylic ugly copolymer (methacrylic acid content 15%)
85 parts by weight and 15 parts by weight of ε-caprolactam oligomer (number average degree of polymerization 15, melting point 213°C, terminal carboxyl group blocked with n-butylamine), ultraviolet absorbers, light stabilizers and other substances listed in Table 2. A sheet was prepared in the same manner as in Example 1 except that a stabilizer was added.

The weather resistance of the sheet obtained in the same manner as in Example 1 was evaluated, and the heat resistance was evaluated by aging at 90° C. for 500 hours.

As a result, in Example 3, in which a large amount of ultraviolet absorber was added, the obtained sheet was slightly colored. Further, the sheet of Example 2 without the heat stabilizer was colored pale yellow after heating at 90° C. for 500 hours, but the sheets of Examples 4 and 5 with the heat stabilizer added had almost no discoloration.

Osaka Soda product 2-hydroxy-4-n-octoxybenzophenone Biosorb 91O: Kyodo Pharmaceutical product ethyl-2-cyano-3,3-diphenylacrylate Tinuvin 312; Ciba Geigy product 2-ethoxy-2°- Ethyloxalizac acid bisanilide below margin Tinuvin 328; Ciba Geigy product 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole

Claims (1)

[Scope of Claims] 1. A graft copolymer obtained by graft copolymerizing 30 to 3% by weight of a polyamide oligomer to 70 to 97% by weight of a zinc ion crosslinked product of an ethylene-α,β unsaturated carboxylic acid copolymer. A resin composition with improved weather resistance, which is obtained by adding a benzotriazole ultraviolet absorber and a hindered amine light stabilizer to a polymer. 2. The resin composition according to claim 1, wherein the resin composition contains a hindered phenol compound stabilizer and/or a phosphorus compound stabilizer. 3. The resin composition according to claim 1 or 2, wherein the polyamide oligomer is a couple lactam oligomer having a number average degree of polymerization of 6 to 35.