JPS5820980B2 - polyamide resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide resin composition that has excellent impact resistance, and particularly to a polyamide resin composition that provides excellent impact resistance even in a structure having a notch shape.

Polyamide resins have excellent physical properties such as toughness and abrasion resistance, so they are widely used as engineering plastic materials in various fields.

However, even these excellent performances are still not fully satisfactory depending on the application, and further performance improvements are required in order to expand the application and improve quality.

For example, although its impact resistance is at a high level compared to other resins, it is well known that impact strength decreases markedly in structures that have a notch shape with a particularly large curvature. There is a strong demand in the market for resins that provide excellent impact strength even in structures having such structures.

The inventors of the present invention have previously discovered that impact resistance can be significantly improved by mixing a specific rubbery substance with polyamide resin.
A patent application was filed as No. 686.

The composition of the polyamide resin and a specific rubber-like substance described in the patent application can significantly improve its impact resistance simply by kneading it with a single screw, but it has the disadvantage that the appearance strength of the welded part during injection molding is poor. It had

In order to improve the appearance of this weld part, the present inventors conducted further research on the amount of lead and arrived at the present invention.

That is, the present invention provides (1) 100 parts by weight of polyamide resin, (2) epoxy equivalent of 600 to 150,000 parts by weight.
Modified olefin rubber 5 to 100 into which epoxy groups have been introduced
This is a polyamide resin composition in which 0.05 to 10 parts by weight of a lubricant is blended with respect to 100 parts by weight of the above-mentioned components (1) and (2).

According to the present invention, the olefin rubber has excellent compatibility with the polyamide resin, a uniform blend having a sea and island state suitable for reinforcement can be obtained, and the molded product obtained from the blend has a sufficiently rubbery state even when deformed at high speed. A composition exhibiting the following can be provided.

Furthermore, by introducing an epoxy group into the olefin rubber, the interfacial adhesion between the matrix phase and the dispersed layer can be increased, resulting in a marked improvement in impact resistance.

Even a structure having a notch shape with a large curvature can exhibit excellent impact resistance.

Further, by adding a specific amount of a lubricant, the impact resistance can be further improved, and the appearance of the weld portion can be improved, which is a great feature in practical use.

Furthermore, the compositions of the present invention possess many other excellent properties of polyamide resins, such as mechanical properties, chemical properties,
It also has the characteristic of maintaining electrical properties, thermal properties, etc.

Although it is unclear why the method of the present invention provides a weld with excellent impact resistance and improved appearance, the lubricant changes the surface properties of the epoxy group-introduced modified olefin rubber, which is the dispersed layer, and the polyamide resin In order to improve dispersibility and dispersion stability in the injection molding process, reaggregation of dispersed particles due to shear force during injection molding is suppressed, and a more uniform dispersion state is formed to improve interfacial adhesion between polyamide resin and modified olefin rubber. This is thought to be because the force is increased.

However, in any case, the improvement in the appearance of the weld area due to the addition of a lubricant is an effect that can only be seen when using modified olefin rubber, and is surprising because it is not seen with unmodified olefin rubber.

The polyamide resin used in the composition of the present invention is not particularly limited, but polyamide resins having an amine group or a carboxyl group are particularly preferable, such as ordinary nylon 6, nylon 6.6, nylon 6.10, nylon 11, and nylon 12. , nylon 6.12, polyhexamethylene diamine terephthalamide, polyhexamethylene diamine isophthalamide, xylene group-containing polyamide, etc.
These can also be used as a mixture or copolymer of two or more types.

However, particularly preferred polyamide resins are nylon 6, nylon 6.6, nylon 6/6.6, xylene group-containing polyamides, and the like.

In addition, modified olefin rubbers containing epoxy groups used in the present invention include ethylene, propylene, butylene,
Ethylenically unsaturated monomers containing epoxy groups are added to olefinic rubbers mainly consisting of one or more α-olefins such as isobutylene, pentene, and hexene, and initiators such as peroxide, heat, light, and ionizing radiation are applied. Copolymers obtained by copolymerizing an olefin monomer and an epoxy group-containing ethylenically unsaturated monomer in the production of olefin rubber can be mentioned.

Examples of the olefin rubber include rough rubber, ethylene rubber, which exhibits thermal stability in melt blending with polyamide resin.
Preferred are propylene rubber, ethylene/butylene rubber, other ethylene/α-olefin copolymers, ethylene/acrylic acid ester copolymers, and the like.

The olefin rubber usually has a glass transition point of 0°C or lower, preferably -20 to -120°C.

Furthermore, in consideration of versatility, economy, modification effect, etc., modification by graft polymerization is particularly preferred.

Examples of the epoxy group-containing ethylenically unsaturated monomer include glycidyl acrylate, glycidyl methacrylate, vinyl glycidyl ether, allyl glycidyl ether, methallyl glycidyl ether, as well as glycidyl ether of hydroxyalkyl acrylate or hydroxyalkyl methacrylate. Two or more types can also be used in combination.

The amount of epoxy groups introduced in modified olefin rubber with epoxy groups depends on the modification method, but the amount of epoxy groups introduced is 6 in terms of epoxy equivalent.
00 to 150,000, preferably 800 to 50
,000.

Here, the epoxy equivalent is expressed as the number of grams of resin containing 1y equivalent of epoxy groups.

In general, when modifying by graft polymerization, it is necessary to introduce a larger number of epoxy groups, that is, a smaller epoxy equivalent, than when modifying by copolymerization, due to the degree of polymerization of graft chains, the formation of homopolymers, etc.

In either method, if the epoxy equivalent is less than 600, disadvantages such as significant thickening, gelation, or impairing moldability occur, while if it is more than 150,000, the effect of improving impact resistance is poor.

In addition, other ethylenically unsaturated monomers other than the epoxy group-containing ethylenically unsaturated monomer may be used in combination to modify the olefin rubber as long as the compatibility with the polyamide resin and physical properties do not deteriorate. can.

The lubricants used in the present invention include monoamides such as higher fatty acid amides, amide lubricants such as bisamides such as ethylene bisamide and methylene bisamide, alcohol lubricants such as higher alcohols having 10 or more carbon atoms, and fatty acids. and IWJ alcohol esters, fatty acid and polyhydric alcohol esters, ester lubricants such as montan wax and carnauba wax, and saponified products obtained by partially saponifying the ester lubricants with alkali metals or alkaline earth metals such as Na, Ca, etc. , curing lubricants with OH groups in the molecule, which are hydrogenated products of natural oils and fats such as whale oil, liquid paraffin with 16 to 40 carbon atoms, paraffin wax, synthetic wax, polyolefin wax (molecular weight 1000 to 10000), oxidized polyolefin wax. Examples include, but are not limited to, hydrocarbon lubricants such as stearic acid, fatty acid lubricants such as calcium stearate, chlorinated naphthalenes containing 1 to 8 chlorines, and ureido compounds having higher alkyl groups. It's not something.

The above lubricants can be used alone or in combination of two or more,
In particular, amide-based lubricants, ester-based lubricants or their partially saponified products, alcohol-based lubricants, and fatty acid-based lubricants are preferred.
Among these, fatty acid monoamides, cyamite, fatty acid esters, or partially saponified products thereof are particularly preferred.

Polyamide resin and epoxy group-introduced modified olefin rubber (
The blending ratio of the modified olefin rubber (hereinafter referred to as modified olefin rubber) depends on the type of the rubber, the purpose of the molded product, etc., but the latter is usually 5 to 100 parts by weight, preferably 8 to 50 parts by weight, per 100 parts by weight of the former. be.

If the amount of modified olefin rubber is less than 5 parts by weight, the effect of improving impact resistance will be poor, while if it is more than 100 parts by weight, other mechanical properties and heat distortion temperature will be lowered.

The amount of the lubricant is usually 0.05 to 10 parts by weight, preferably 0.15 to 5 parts by weight, per 100 parts by weight of the polyamide resin and modified olefin rubber.

If it is less than 0.05 parts by weight, it will be less effective in improving the appearance of the weld area, and if it is more than 10 parts by weight, problems such as bleeding will occur.

The method for producing the resin composition of the present invention is not particularly limited, and for example, a modified olefin rubber and/or a lubricant may be co-present during polymerization of a polyamide resin and mixed with the missing component after polymerization, or an olefin rubber and an olefin rubber may be produced. It can be made by pre-mixing a lubricant and blending it with the polyamide resin, or by solution blending the three components, but it is usually preferable to mix the lubricant with the polyamide resin in an extruder, mixing rack, kneader, reaction vessel, etc. Made by melt blending modified olefin rubber and lubricant.

Furthermore, a polyamide resin and a modified olefin rubber may be mixed in advance and pelletized, and a lubricant may be added by triblending during melt processing such as extrusion or injection molding.

The compositions of the present invention, in particular, can be simply kneaded in a melt blend to obtain a resin composition in which at least some chemical reaction has occurred between the polyamide resin and the modified olefin rubber.

The composition of the present invention may further contain other components as desired depending on the application, such as fillers, reinforcing agents, flame retardants, antistatic agents, stabilizers, dyes and pigments, anti-slip agents, mold release agents, nucleating agents, Additives such as foaming agents can also be blended.

The composition of the present invention retains the excellent moldability of polyamide-based resins, and depending on the molding method, has superior moldability than polyamide-based resins, so special molding conditions are not required. , it can be molded under the usual molding conditions for polyamide resins.

And a wide range of molded products, such as various molded parts, films, sheet-like products, fibrous products, tubular products, plate-like products, laminates,
In addition to molding containers, it can be widely used in coatings, adhesives, impregnating agents, cushioning materials, etc.

The composition of the present invention is suitable for reinforcing the polyamide resin and the modified olefin rubber, and furthermore, the dispersion stability of the modified olefin rubber is further improved by using a lubricant, so it can be used over a wide composition range. One of the major features is that it is uniform and does not cause drift during melt molding because at least some chemical bonds are formed between the polyamide resin and modified olefin rubber.

The present invention will be explained below with reference to Examples, but of course the present invention is not limited to the Examples in any way.

Note that parts in the examples represent parts by weight. Moreover, the physical property values in the examples are values measured according to JIS K6810-70 "Polyamide resin molding material testing method".

In addition, regarding the appearance of the weld part, if the molded product looks pearl-like no matter which direction you look at it, it is bad; if it looks pearl-like in a certain angle range (c), if it looks pearl-like from any angle. What cannot be seen is expressed as 0.

Example 1 100 parts of an ethylene/α-olefin copolymer (Tafmer P0180Tg, approximately -70°G, manufactured by Mitsui Petrochemicals) and 10 parts of glycidyl methacrylate are melt-mixed.

Add 0.6 parts of dicumyl peroxide to this mixture,
React at 150°C for 30 minutes to obtain an epoxy equivalent of approximately 1600.
A graft modified copolymer having a Tg of about -70°C was obtained.

This graft modified copolymer and nylon 6 resin (Toyobo-
Nylon T820) was premixed in pellet form at the blending ratio shown in Table 1, and then blended in a molten state at a temperature of 250°C using a 40mmQf vented extruder to form pellets of 3mmQ5 x 3mmL. I got it.

After the pellets were completely dried, they were triblended with an amide lubricant (Hoechst Wax C, Hoechst Japan Co., Ltd.) in the proportions shown in Table 1, and then processed using an injection molding machine (Nissei Jushi Co., Ltd., FS75).
JIS 6810- at a molding temperature of 240-265-270°C, an injection pressure of 70~, and a metal temperature of 60°C.
A test piece specified in No. 70 was molded.

Izotsu impact strength of the obtained test piece when completely dry (
Table 1 shows the measurement results (with a V-notch) and the evaluation results of the appearance of the weld part (made by molding a tensile test piece with two gates at both ends).

We also conducted similar experiments using an unmodified ethylene/α-olefin copolymer as a comparative example, and the results are shown in the table below.
1 is displayed all at once.

As is clear from Table 1, the composition using a modified olefin copolymer and a lubricant in combination provided an improved weld appearance.

On the other hand, in a comparative example (/16.2) in which a lubricant was added to the unmodified olefin copolymer system, the impact strength was slightly improved, but the appearance of the weld part was not improved at all.

Furthermore, if 15 parts of a lubricant is used in combination, molding becomes virtually impossible.

Example 2 A modified copolymer having an epoxy equivalent of about 1500 was obtained in the same manner as in Example 1 except that the amount of glycidyl meccrylate was changed.

A mixture of 30 parts of the obtained modified copolymer and 100 parts of nylon 6 resin was made into 100 parts, and bisamide (Japan Hydrogen Industry Co., Ltd.) was mixed in the proportions shown in Table 2.

The resulting mixture is melt-kneaded and pelletized using a 40 mm Q5 single-screw extruder.

The obtained pellets were molded in the same manner as in Example 1, and the physical properties and appearance were evaluated.

The results are shown in Table-2. As is clear from Table 2, the appearance and impact resistance of the weld portion could be improved by adding the lubricant.

However, if the amount of lubricant added is as large as 15 parts, not only will pelletizing with an extruder be extremely difficult, but the lubricant will bleed onto the surface of the molded product, resulting in a deterioration of the surface condition.

Example 3 After premixing 20 parts of the modified olefin copolymer used in Example 1 and 100 parts of nylon 6 (Toyobo Co., Ltd. Nylon T802), pellets were obtained in the same manner as in Example 1.

Next, 0 parts of the various lubricants shown in Table 3 were added to 100 parts of the pellets.
．． A 5-part tri-blend was prepared and injection molded in the same manner as in Example 1.

The results are shown in Table-3.

The appearance of the weld was improved by adding a lubricant, but the impact strength was particularly good for amide types, ester types, and partially saponified esters, followed by alcohol types.

Claims (1)

[Scope of Claims] 1 (1) 100 parts by weight of a polyamide resin, (2) 5 to 100 parts by weight of a modified olefin rubber into which epoxy groups with an epoxy equivalent of 600 to 150,000 have been introduced, and the above component (1). and component (2) in total of 100 parts by weight.
A polyamide resin composition containing 05 to 10 parts by weight of a lubricant. 2. The composition according to claim 1, wherein the modified olefin rubber has a glass transition point of -20 to -120°C. 3. The composition according to claim 1, wherein the lubricant is at least one selected from Nisder-based lubricants or partially saponified products thereof, amide-based lubricants, alcohol-based lubricants, and fatty acid-based lubricants. 4. The composition according to claim 1 or 3, wherein the lubricant is at least one selected from fatty acid monoamides, cyamite, fatty acid esters, or partially saponified products thereof.