JPH03215555A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition excellent in moldability, heat resistance, rigidity, water resistance and surface properties by adding a layered silicate to a mixture of a polyamide resin with an aromatic vinyl homopolymer or copolymer. CONSTITUTION:A resin composition comprising a polyamide resin (A), an aromatic vinyl homopolymer or copolymer (B) and a layered silicate (C) homogeneously dispersed in components A and/or B. The mixing ratio is such that about 0.05-30 pts.wt. component C is mixed with 100 pts.wt. mixture of about 10-90wt.% component A with about 90-10wt.% component B. A desirable component A is a resin having an average mol.wt. of 9000-30000. A desirable component B is polystyrene, an acrylonitrile/butadiene/styrene graft polymer or the like. Examples of component C include montmorillonite, hectorite, beidellite and nontronite, and especially montmorillonite is desirable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has excellent moldability, and its molded products have excellent heat resistance, rigidity, water resistance, surface properties, and impact resistance (surface impact resistance). It relates to a resin composition having. [Prior Art] Polyamide resins generally have excellent abrasion resistance, impact resistance, moldability, chemical resistance, and mechanical strength, but they suffer from problems such as a decrease in rigidity and dimensional changes when water is absorbed. be.

Materials mixed with glass fibers or inorganic fillers have traditionally been used to reduce dimensional changes when water is absorbed and to improve the decrease in rigidity when water is absorbed. The field of application has been limited due to problems with surface impact resistance) and surface properties.

Recently, two or more types of polymers have been mixed (
Attempts have been made to solve these problems. An invention has been proposed that maintains the excellent properties of polyamide resin while improving the drawbacks of changes in dimensions and rigidity due to water absorption.

However, when mixing two or more types of polymers to impart different and excellent properties to the resin, the two
Of course, the melting point of seeds or larger polymers is
They often have different properties such as crystallinity and are difficult to mix with each other. Therefore, the key point in alloying technology for polymer alloys is how to make two or more types of polymers compatible and obtain an ideal dispersion shape and particle size.

Normally, it is preferable to have a sea-island horizontal structure in non-phase bay type polymer alloys, which consists of 71-RIX resin that forms the sea area and domain resin that forms the island area, and the dispersed shape of the island area. The particle size has a great influence on physical properties.

Regarding the fractional shape and particle size of these islands (domains), the appropriate dispersion shape and particle size depend on the resin to be combined.
Although the particle size may vary, it is preferred that the average particle size be 1 to 2 pm or less, as stated in many patents.

However, by simply mixing resins, the average particle size of the islands can be reduced by 1
It is difficult to reduce the temperature to 2 pm or less. Therefore, by improving the compatibility of the resins and further devising the mixing method, it is possible to reduce the average particle size to less than 1 to 2 pm.
Several i have been announced.

In addition, there is a theoretical lower limit to the average particle size of the islands, which is beyond the maximum range, but in reality, at the current technological stage, for most combinations of resins, the average particle size of the islands can be It can be said that the key point is to reduce the size and improve physical properties such as impact resistance, moldability, and impact resistance. Regarding the shape, it is better to make it as close to a spherical shape as possible in order to prevent deformation of the molded product.
Regarding uniformity, it is important that there is little variation in the average particle size, and in particular that there are no particles that are extremely large compared to the average particle size.

In one patent, compatibility is achieved by introducing a functional group that has an affinity for the polymer to be alloyed, or by using a third component that has an affinity for each of two or more polymers as a compatibilizer. It is discussed how to improve the physical properties by improving the dispersion of the islands and improving the physical properties. However, with the existing methods, the dispersion of islands is not sufficient;
In particular, even if the average particle size is fine, it is still not sufficient in terms of shape and uniformity, and while covering the desired physical properties, especially the drawbacks due to water absorption of polyamide, it is necessary to improve the heat distortion temperature and impact resistance. Materials or techniques for obtaining materials with excellent, balanced performance have not yet been developed.

[Problems to be solved by the invention] As mentioned above, it is possible to satisfy all the properties of moldability, heat resistance, rigidity, water resistance, surface properties, and impact resistance by modifying conventional polyamides (bolymer alloy, etc.). No material has been developed yet, and there is a strong desire to develop a material that also has these properties.

The inventors of the present invention have conducted intensive research with the aim of developing a resin with excellent moldability, heat resistance, rigidity, water resistance, and surface properties. The present invention was completed by discovering that the objective can be achieved by blending the combination.

1,000 Steps to Solve Question F] The composition of the present invention is a composition based on the morphology of a sea-island structure of two or more resins, and a composition consisting of a combination of a solid material that forms the core of the island part. It is about things. The inorganic material that will serve as the core is selected to match the particle size of the desired island part, is dispersed in a fine state in advance in the resin that will become the island part, and is melted or mixed with the resin that will be the sea part. Blend the pellets and create a composition. Alternatively, when melting and kneading the sea and island parts, an inorganic substance is dispersed and mixed at the same time to create a composition. In some cases, an inorganic substance is previously dispersed in the resin that will form the sea area, and the resin is melt mixed or pellet blended with the tit fat that will form the island area to create a composition. The composition of the present invention improves the dispersion of Shimaya in the polymer alloy obtained by such a method,
It is a composition with uniform particle size and shape, and is further refined.

In the present invention, which of component (A) and component (B) is
The silicate may be contained in either or both of the components (A) and (B), and the silicate present in the island part may cause the island part to become fine and uniform. Those present in the sea area improve the rigidity and heat resistance of the entire resin, and also have a positive effect on the dispersion of the island areas.

The contents will be explained in detail.

The composition of the present invention comprises (A) 10 to 90% by weight of a polyamide resin, and (B) 9% of an aromatic vinyl homopolymer or copolymer.
0 to 10% by weight, and (C) the layered silicate in the (A) 8 and/or (B) components.
) A resin composition comprising 0.05 to 30 parts by weight of the components uniformly dispersed in 100 parts by weight of the total amount of the components.

The polyamide resin of component (A) constituting the composition of the present invention has an acid amide bond (-CONH-) in the molecule, and specifically includes ε-cabrolactam, 6-aminocabrolactam, ω Polymers or copolymers obtained from monoenantholactam, 7-aminohbutanoic acid, l1-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piveridone, etc.: hexamethylenediamine, nonamethylenediamine, undecanoic acid, etc. Examples include polymers or copolymers obtained by polycondensation of diamines such as methylene diamine, dodecamethylene diamine, and mexylylene diamine and dicarboxylic acids such as terephthalic acid, isofucric acid, adibic acid, and sebacic acid, or mixtures thereof. can do. The polyamide resin of component (A) preferably has an average molecular weight of 9,000 to 30,000.

The aromatic vinyl homopolymer used in the present invention is styrene,
It is a polymer of monomers such as α-methylstyrene, methylstyrene, vinylxylene, monochlorostyrene, dichlorostyrene, monobromstyrene, dibromstyrene, p-tert-butylstyrene, ethylstyrene, vinyl, etc. Polystyrene is preferred.

An aromatic vinyl copolymer is a copolymer of an aromatic vinyl monomer and a copolymerizable vinyl monomer, and examples of the vinyl monomer include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile. , acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate 1-, butyl acrylate, and 2-ethylhexyl acrylate, methyl methacrylate, ethylene methacrylate,
Methacrylic acid alkyl esters such as 2-edylhexyl methacrylate, maleimide compounds such as maleimide, N-phenylmaleimide, and N-cyclohexylmaleimide, unsaturated substances such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, and cinnamic acid. Acid, unsaturated carbonic anhydride such as maleic anhydride, itaconic anhydride, chloromaleic anhydride, citraconic anhydride, butenyl succinic anhydride, tetrahydrophthalic anhydride, glycidyl acrylate, glycidyl methacrylate, awalglycidyl ether, 2 - methyl allyl glycidyl ether,
2-methylallyl glycidyl ether, styrene p-
Glycidyl ether, 3.4-epoxybutene, 3.4
- eboxy-3-methyl-1-butene, 3,4-epoxy-1-pentene, 3,4-epoxy-3-methylpentene, 5,6-epoxy-1-hexene, vinylcyclohexene monooxide, Epoxy group-containing unsaturated compounds such as p-glycidylstyrene, amine group-containing unsaturated compounds such as allylamine, aminoethyl meccrylate, aminobrobyl methacrylate, aminostyrene, 3-hydroxy-1-propene, 4-hydroxy-1-butene , cis-4-hydroxy-2-butene, trans-4-
Hydroxy-2-butene, 3-hydroxy-2-methyl-1-broben, cis-5-hydroxy-2-bentene, trans-5-hydroxy-2-bentene, cis-1
．． 4-Hydroxy-2-butene, trans-1,4-hydroxy-2-butene, 2-hydroxyethyl acrylate}, 2-hydroxyethyl methacrylate, 3-hydroxybubutyl acrylate, 3-hydroxybubutyl methacrylate , 2-hydroxyethyl crotonate, 2.3.4.5.6-penkhydroxyhexyl acrylate, 2,3.4.5.6-pentahydroxyhexyl methacrylate, 2.3.4.5-te1 - Other vinyl monomers that can be copolymerized with these aromatic vinyl compounds, such as hydroxyl group-containing unsaturated compounds such as hydroxybentyl acrylate and 2.3.4.5-tethydroxybentyl methacnolate. The body is used in one or more types. Furthermore, it may be a copolymer of these and a cyanogen monomer that can serve as a rubber substrate.

Examples of preferred aromatic vinyl copolymers include polystyrene, acrylonitrile-butadiene-styrene graft polymer, styrene/maleic anhydride copolymer, styrene/N-phenylmaleimide copolymer, styrene/maleic anhydride/N - phenylmaleimide copolymer, styrene/methacnolic acid copolymer, styrene glycidyl methacrylate copolymer, etc. Component (B) has a flexural modulus of 10.000 kg/cm, unlike the impact resistance improving material.
“It says more than that.

The distribution ratio of components (A) and (B) is that component (A) is 10
90 parts by weight, and component (B) is 90 to 10 parts by weight. If the blending ratio of component (A) is less than 10 parts by weight, moldability will decrease, and if it exceeds 90 parts by weight, rigidity upon water absorption will decrease.

Component (C) is a layered silicate. This component (C) is used to replace component (B) with (A) in a molded article obtained from a resin composition.
It is a substance that contributes to finely dispersing component (A) in the polyamide of component () or component (B), and imparting mechanical properties with excellent moldability, heat resistance, and surface impact resistance. .

Furthermore, the uniformly dispersed layered silicate has the characteristic of imparting rigidity and finely dispersing the resin that becomes the dispersed particles, and simultaneously satisfies rigidity and impact resistance (surface impact resistance), which are conventionally contradictory properties. This is an essential component for providing a multi-component polymer blend stabilization method that is completely different from known techniques for imparting stiffness and impact resistance.

The layered silicate is characterized in that when dispersed in component (A), each layer maintains an average interlayer distance of 20 or more and is uniformly dispersed. In the present invention, a layered rare acid salt refers to one unit of a substance having a side of 0.002 to 1)/Ml and a thickness of 6 to 2 OA.

In addition, the interlayer distance refers to the distance between the centers of gravity of flat plates of layered silicate, and uniform dispersion means that each sheet of layered silicate is distributed in parallel, or that many layers with an average overlap of 5 or less layers are distributed in parallel. , or randomly, or in a mixed state of parallel and random, 50% by weight or more, preferably 70% by weight or more, is dispersed without forming local lumps.

As a raw material for such a layered silicate, a layered phyllosilicate mineral composed of magnesium silicate or aluminum silicate can be exemplified. Specifically, examples include smectite clay minerals such as montmorillonite, saponite, beidellite, nontronite, hectorite, and sudibunsite, as well as vermiculite and paroysite, which may be natural or synthetic. Among these, montmori kuchinite is preferred.

The mixing ratio of component (C) is 0.405 to 30 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the total amount of components (A) and (B). When the blending ratio of component (C) is less than 0.05 parts by weight, the effect of improving the heat resistance and impact resistance of the molded product is small, and when it exceeds 30 parts by weight, the fluidity of the resin composition is extremely reduced. However, the moldability decreases. Furthermore, in addition to the above-mentioned components (A), (B), and (C), impact resistance modifiers can be added to the present invention as needed. The impact resistance improving material is not particularly limited as long as it is an impact resistance improving material used for -FIi and polyamide, and the following materials may be used. When 20% by weight is added to polyamide, its impact resistance is more than doubled, and its flexural modulus is 10. 0 0 0 kg/
cm2 or less.

Examples of impact resistance modifiers include styrene-butadiene (or isoprene) copolymers (random copolymers, block copolymers, hydrogenated block copolymers, and graft copolymers) that are elastomeric at room temperature; An example is a copolymer of polyolefins. Specifically, styrene-butadiene random copolymer, styrene-butadiene-styrene block copolymer, styrene-isobrene-styrene block copolymer, hydrogenated styrene-butadiene-styrene block copolymer, hydrogenated styrene-isoprene- Styrene block copolymer. Examples include copolymers of two or more olefins derived from ethylene, propylene, butene-1, hexene-1, decene-1, and 4-methylbutene-4-methylbenten-1.

This impact resistance improving material can be modified with unsaturated carboxylic acid or the like.

A preferred blending amount of the impact resistance modifier is 30 parts by weight or less based on 100 parts by weight of the total amount of components (A), (B), and (C). If it exceeds 30 parts by weight, moldability decreases,
This is not preferred because the heat resistance of the molded product decreases.

The phase foil forming agent is, for example, 70 parts by weight of (C)-2 poly(ethylene/glycidyl methacrylate) copolymer (ethylene/glycidyl methacrylate = 85/15) and poly(acrylic acid) having a peroxide bond in the side chain. butyl-b-styrene)
(butyl acrylate/styrene - 10/90) and 30 parts by weight were melted at 200±20°C using a melt extruder.
c' Poly(ethylene/glycidyl methacrylate) obtained by melt-kneading 1 g-Poly(butyl acrylate) b-
A grafted polyolefin modified product (grade name: Modiper-A4100 manufactured by Nihon Yushi Co., Ltd., manufactured by Kyoiku Co., Ltd.), which is styrene), may be used.

The composition of the present invention may contain dyes, pigments, nucleating agents,
Fillers such as mold release agents, reinforcing agents such as glass fiber, metal fiber, carbon fiber, plasticizers, lubricants, heat resistance imparting agents, foaming agents,
Flame retardants and the like can be added.

The method for producing the resin composition of the present invention is not particularly limited. For example, after the layered silicate of component (C) is brought into contact with a swelling agent to expand the interlayers and make it easier to incorporate monomers between the layers, the monomers forming component (A) are mixed and polymerized (in Japanese Patent Application Laid-open No. (Refer to Publication No. 62-74957)
and further mix the thermoplastic resin of component (B), 23
A method of melt-kneading at 0 to 250°C, preferably 250 to 320°C; a thermoplastic resin as component (B) is melted in polyamide in a molten state after completion of polymerization;
It is possible to apply a method of kneading and blending the layered silicate of component (C) in which the interlayer distance is expanded to 50 or more in advance.

In the resin composition of the present invention, it is preferable that particles that can become dispersed particles have a number average particle diameter of 2p7n or less and form a dispersed phase.

The layered silicate of component (C) may be dispersed in both the phases of component (A) and component (B), or may be dispersed in one of the phases.

In the present invention, by further blending a layered silicate into the mixture of components (A) and (B), both the heat resistance and impact resistance of a molded article can be improved at the same time. Generally, when an inorganic filler is blended into a mixture of polyamide resin and thermoplastic resin, rigidity and heat resistance can be improved, but impact resistance is reduced.

However, in the composition of the present invention, the layered silicate is dispersed in a very fine state, and even with a small amount of addition, rigidity and
It is thought that the heat resistance is improved, and since the domains can be finely dispersed with small particle diameters in the dispersion of the polymers, the rigidity, heat resistance, and impact resistance are also improved.

- The resin composition of the present invention can be used as a manufacturing material for various automobile parts, electronic and electrical parts, mechanical parts, and general miscellaneous goods.

(Example) Hereinafter, the non-invention will be explained in more detail with reference to Examples. Note that parts represent parts by weight. Moreover, the test method for each characteristic shown below is as follows.

Tensile strength... ASTM D-6 3 8
Bending strength, bending modulus/ASTM D-790 Izod test 12 strength: . ASTM D-2
5 6 Heat distortion temperature ASTM D-648 High speed impact strength: Firstly, the resin composition of the present invention has a
was formed into a disk with a thickness of 3.2 mm and a diameter of 100 mm, and the disk was used as a test piece. Next, the tip diameter is 1/2 at 30°C.
An inch round missile was placed in the center of the previous test piece at 25m/
A surface impact measurement method (UBE method) was used in which the fracture energy was calculated from the area of the stress-strain curve at the time of fracture by dropping the specimen at a speed of seconds.

Dispersed Particle Diameter A small piece of each molded body was split using a cyclotome, and the small piece was stained with Roguemin B, washed with water, and then the dispersed particle size in the small piece was measured using an optical microscope (xlo00).

Examples and Comparative Examples Resin compositions were produced using the combinations and blending ratios of each component shown in the table below, and test pieces for each characteristic evaluation were produced as molded bodies.

(.A) 200g of montmorillonite with an average thickness of one unit of polyamide layered silicate of 965 people and an average side length of about 0.1μm
was dispersed in 102 g of water, 512 g of 12-aminododecanoic acid and 24-g of concentrated hydrochloric acid were added thereto, stirred for 5 minutes, and then passed through two doors.

Furthermore, after thoroughly washing this, it was vacuum dried.

Through this operation, a complex of ammonium 12-aminododecanoate ion and montmorillonite was prepared. The layered silicate content in the composite was 80% by weight. Furthermore, X-ray diffraction measurements of this composite revealed that the silicate interlayer distance was 18
There were 0 people.

Next, 10 kg of ε-1-cubic lactam, 1 kg of water, and 200 g of the dried composite were placed in a reaction vessel equipped with a stirrer, and stirred at 100'C so that the inside of the reaction system became uniform. The temperature was further increased to 260'C and stirred for 1 hour under a pressure of 15 kg/cm2. Thereafter, the pressure was released and the reaction was carried out under normal pressure for 3 hours while evaporating water from the reaction vessel. After the reaction was completed, the reaction product taken out in the form of a strand from the lower nozzle of the reaction vessel was cooled with water and canted to obtain a pellet made of polyamide resin (average molecular weight 15.000) and montmorillonite. Next, the pellets were immersed in hot water to extract and remove unreacted monomers (about 10%), and then dried in vacuum. The ratio of polyamide and montmorillonite in this dry pellet is 100% of polyamide resin.
The amount of montmorillonite was 16 parts by weight.

(B) Aromatic vinyl homopolymer or copolymer Styrene/maleic anhydride copolymer (Arcobonoma = (Kiyusei grade name, Guiraku 232, hereinafter abbreviated as SMA H) Impact resistance modifier Hydrogenated styrene butadiene block Copolymer (grade name manufactured by Shell Chemical ■, Kraton G1651, hereinafter SEBS)
) The molded body was manufactured by the following method. First, the amounts of each component shown in the table were premixed, and then melted and mixed at 250°C to 300°C using an extruder with a screw diameter of 30 mm to form pellets. After that, the pellets were vacuum dried, and then molded using an injection molding machine at a cylinder temperature of 250 to 300°C.
Injection molding was performed at a mold temperature of 80°C to obtain a molded product.

The obtained molded bodies were used as test pieces for each characteristic evaluation, and evaluation tests were conducted. The results are shown in the table.

(Effects of the Invention) As shown in the results in the table, by further blending a layered silicate into the mixture of polyamide and thermoplastic resin, not only the rigidity but also the impact resistance was improved.

Claims (1)

[Scope of Claims] (A) polyamide resin, (B) aromatic vinyl homopolymer or copolymer, and (C) layered silicate uniformly dispersed in components (A) and/or (B). A resin composition consisting of.