JPH0912873A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin compsn., capable of forming a molded product excellent in heat resistance, mechanical strength and impact resistance. SOLUTION: This thermoplastic resin compsn. comprises (A) 100 pts.wt. resin mixture of (a) 99-10wt.%, polyamide resin contg. 0.01-50wt.%, swelling fluoromica mineral with (b) 1-90wt.%, hard styrene polymer, and (B) 0.01-10 pts.wt. thermoplastic elastomer blended therewith.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyamide resin,
The present invention relates to a thermoplastic resin composition which comprises a specific swelling fluoromica-based mineral, a styrene-based hard polymer and a thermoplastic elastomer and can be formed into a molded article excellent in heat resistance, mechanical strength and impact resistance.

[0002]

2. Description of the Related Art Polyamide resins are widely used as molding parts for automobiles, home appliances and electronic devices because they are excellent in mechanical strength and heat resistance. However, in the case of automobile applications, since it is used under particularly severe conditions,
It is necessary to further improve the impact resistance of the obtained molded body.

Conventionally, there has been known a method in which glass fibers are mixed with a polyamide resin to improve impact resistance (Japanese Patent Publication No.
No. 9465), the mechanical strength and the dimensional stability are improved, but the impact resistance is not sufficient.

It is also known that impact resistance is improved by adding a block copolymer or a modified block copolymer to a polyamide resin. For example, a resin composition comprising a partially hydrogenated block copolymer and a polyamide resin (Japanese Patent Publication No. Sho 60-11941), a diene portion of a copolymer of a conjugated diene and a vinyl aromatic hydrocarbon, or a carboxyl group or its A resin composition comprising a modified block copolymer having a derivative introduced therein and a polyamide resin (JP-A-58-
No. 7443), and a resin composition comprising a hydrogenated polymer of a conjugated diene / or a maleic anhydride adduct of a hydrogenated copolymer of a conjugated diene and a vinyl aromatic hydrocarbon, and a polyamide resin (JP-A-59-59). No. 564514) is disclosed, but these resin compositions all have reduced mechanical strength and heat resistance, and poor moldability, so that a molded article having an excellent appearance can be obtained. There wasn't.

Further, JP-A-62-149749 discloses a resin composition in which a styrene-based polymer, an inorganic filler and a styrene-based thermoplastic elastomer copolymer are blended with a polyamide resin. When molding is performed with a large amount of the elastomer compounded, impact resistance is improved, but there is a problem that mechanical strength and heat resistance are reduced.

On the other hand, the present inventors have found that a resin composition comprising a polyamide resin and a specific swelling fluoromica-based mineral,
It was found that a molded product having excellent mechanical strength, toughness, heat resistance and dimensional stability can be provided, and a patent application was previously made (Japanese Patent Laid-Open No. 6-248176). However, the resulting molded product has insufficient impact resistance. There wasn't.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a thermoplastic resin composition which can be formed into a molded article having extremely good impact resistance and excellent heat resistance and mechanical strength. is there.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a polyamide resin containing a specific swelling fluoromica-based mineral and a styrene-based hard polymer. The present inventors have found that this object can be achieved by blending a thermoplastic elastomer with a resin mixture consisting of That is, the gist of the present invention is to provide (A) (a) a swellable fluoromica-based mineral in an amount of 0.01 to
Polyamide resin containing 50% by weight 99 to 10% by weight and (b)
For 100 parts by weight of a resin mixture consisting of 1 to 90% by weight of a styrene-based hard polymer, (B) a thermoplastic elastomer of 0.
A thermoplastic resin composition is characterized by being blended in an amount of 01 to 10 parts by weight.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The polyamide resin used in the present invention means a melt-moldable polymer having an amide bond formed from an amino acid, a lactam or a diamine, and a dicarboxylic acid. Examples of monomers forming such a polyamide resin include the following.

As the amino acid, 6-aminocaproic acid,
Examples include 11-aminoundecanoic acid, 12-aminododecanoic acid and para-aminomethylbenzoic acid.

As the lactam, ε-caprolactam, ω
-Laurolactam, etc.

As the diamine, tetramethylenediamine, hexamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 2, 4-dimethyloctamethylenediamine,
Meta-xylylenediamine, para-xylylenediamine, 1,
3-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 3,8-bis (aminomethyl) tricyclodecane, bis (4-aminocyclohexyl) methane, bis (3-Methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine and the like.

The dicarboxylic acids include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2
-Chloroterephthalic acid, 2-Methylterephthalic acid, 5-
Examples include methyl isophthalic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and diglycolic acid.

Preferred as the polyamide resin used in the present invention are polycaproamide (nylon 6),
Polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (Nylon 116), polyundecane amide (nylon 11), polydodecane amide (nylon 12),
Polytrimethylhexamethylene terephthalamide nylon TMHT), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthal / isophthalamide (nylon 6T / 6I), polybis (1-aminocyclohexyl) methandodecamide (nylon PACM12), polybis (3-Methyl-4-aminocyclohexyl) methandodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylene hexahydroterephthalamide ( Nylon 11
T (H)) and copolyamides and mixed polyamides thereof. Among them, particularly preferred are nylon 6, nylon 46, nylon 66, nylon 11, nylon 12, copolymerized polyamides thereof, and mixed polyamides.

The polyamide resin used here is usually produced by a known melt polymerization method, or by using a solid phase polymerization method in combination therewith.

The relative viscosity of the polyamide resin used in the present invention is not particularly limited, but phenol / tetrachloroethane = 60/40 (weight ratio) is used as a solvent at a temperature of 25 ° C.
The relative viscosity determined under the condition of a concentration of 1 g / dl is preferably in the range of 1.5 to 5.0. If the relative viscosity is less than 1.5, the mechanical properties of the molded product deteriorate, which is not preferable. On the contrary
When it exceeds 5.0, the moldability of the resin composition rapidly decreases, which is not preferable.

The swellable fluoromica-based mineral used in the present invention is obtained by heat-treating a mixture of talc and sodium and / or lithium silicofluoride or fluoride. As a specific method, there is a method disclosed in Japanese Patent Laid-Open No. 2-149415. That is, this method uses talc as a starting material, and intercalates sodium ions and / or lithium ions into the starting material to obtain a swellable fluoromica-based mineral. In this method, talc is mixed with silicofluoride and / or fluoride, and is mixed in a magnetic crucible for about 700 to 1200.
Fluorine mica-based mineral can be obtained by a short-time heat treatment at ℃. The swellable fluoromica-based mineral used in the present invention is particularly preferably one produced by this method.

To obtain a swellable fluoromica-based mineral,
The metal constituting the silicofluoride or fluoride must be sodium or lithium among the alkali metals. These alkali metals may be used alone or in combination. Among the alkali metals, potassium is not preferable because it does not give a swelling fluoromica mineral, but it may be used in combination with sodium or lithium and may be used for the purpose of adjusting the swelling property in a limited amount. It is possible. Further, the amount of silicofluoride and / or fluoride mixed with talc is preferably in the range of 10 to 35% by weight of the total mixture, and if the amount is out of this range, the yield of swelling fluoromica-based minerals is reduced.

The swellable fluoromica-based mineral produced by the above method has a structure represented by the following general formula (1). α (MF) · β (aMgF ₂ · bMgO) · γSiO ₂ (1) (In the formula, M represents sodium or lithium, and α,
β, γ, a and b each represent a coefficient, and 0.1 ≦ α ≦ 2
, 2 ≦ β ≦ 3.5, 3 ≦ γ ≦ 4, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1
, A + b = 1. )

The term "swelling property" as used in the present invention means that the fluoromica-based mineral absorbs polar molecules such as amino acids, nylon salts and water molecules or cations between the layers to increase the interlayer distance or further swelling and cleavage. The characteristic is that the particles become ultrafine particles. The fluoromica-based mineral represented by the formula (1) exhibits such swelling property.

The swellable fluoromica-based mineral used in the present invention has a layer thickness in the c-axis direction of 9 to 20Å as measured by the X-ray powder method.
belongs to.

In the step of producing the swellable fluoromica-based mineral used in the present invention, a small amount of alumina (Al ₂ O ₃ ) may be added to adjust the swellability of the swellable fluoromica-based mineral produced. is there.

Although various methods can be used to disperse the swellable fluoromica mineral in the polyamide resin, a predetermined amount of the swellable fluoromica mineral is present in the monomer forming the polyamide resin. The method of polymerizing in the state is particularly preferable. In this case, the swellable fluoromica-based mineral is sufficiently finely and uniformly dispersed in the polyamide resin, and the effect of the present invention is most remarkable.

The content of the swellable fluoromica-based mineral is preferably 0.01 to 50% by weight, and preferably 0.1 to 20% by weight, based on the total amount of the mixture (a) of the polyamide resin and the swellable fluoromica-based mineral. Is particularly preferable. If the blending amount is less than 0.01% by weight, the effect of improving mechanical strength, heat resistance and dimensional stability cannot be obtained, and if it exceeds 50% by weight, the toughness is greatly reduced, which is not preferable.

The styrenic hard polymer used in the present invention is

[0027]

Embedded image

(Wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Z represents a halogen atom, a hydroxyl group or an alkyl group having 1 to 4 carbon atoms, and p represents an integer of 0 to 5). The repeating unit represented by the formula (1) is contained in the polymer in an amount of 25% by weight or more. Examples of such styrenic polymers include homopolymers and copolymers of styrene or its derivatives.

Specific examples of the homopolymer include polystyrene, poly-α-methylstyrene, polyvinyltoluene,
Examples thereof include poly-p-hydroxystyrene and poly-p-chlorostyrene. Further, specific examples of the copolymer include styrene / maleic anhydride copolymer, styrene / methyl methacrylate copolymer, styrene / acrylonitrile copolymer, styrene / α-methylstyrene copolymer, styrene / vinyltoluene copolymer. Examples thereof include polymers. Among these, polystyrene and styrene / maleic anhydride copolymer are particularly preferable.

The compounding amount of the styrene-based hard polymer (b) is
1 to 1 of the whole resin mixture (A) of a polyamide resin containing a swelling fluoromica-based mineral and a styrene-based hard polymer
90% by weight is preferred and 2-50% by weight is particularly preferred. If the blending amount is less than 1% by weight, the effect of improving impact resistance is insufficient, and if the blending amount exceeds 90% by weight, heat resistance and mechanical strength are remarkably lowered, which is not preferable.

The thermoplastic elastomer used in the present invention is substantially molded from the resin composition by adding a small amount to a mixture of a polyamide resin containing a swelling fluoromica-based mineral and a styrene-based hard polymer. It is a component that can improve the impact resistance of the body.

As the thermoplastic elastomer (TPE), styrene TPE, olefin TPE, urethane TPE, ester TPE, polyvinyl chloride TPE, and butyl rubber graft polyethylene,
Rubber-based TPEs such as 1,2-polybutadiene, trans-1,4-polyisoprene, ionomers and natural rubber are used, and styrene-based TPEs are particularly preferable.

Styrenic TPE is defined as a block polymer having polystyrene as a hard segment and a rubbery polymer such as polybutadiene, polybutylene and polyisoprene as a soft segment (edited by the Society of Polymer Science, New Polymer Materials). One Point 19 "Elastomer", p. 63, Kyoritsu Publisher, 1989).

In the present invention, a diene rubber component such as polybutadiene is used as a central block portion (soft segment), and a polyvinyl aromatic hydrocarbon component such as polystyrene is used as an end block portion (hard segment).
And a hydrogenated product of such a block copolymer are preferable.

Examples of the terminal block portion of the styrene-based TPE include vinyl aromatic hydrocarbon polymer composed of styrene, α-methylstyrene, vinyltoluene, vinylxylene and a mixture thereof. May be a homopolymer or a heteropolymer. Also, for the central block part,
For example, butadiene, isoprene, 1,3-pentadiene,
Examples thereof include a rubbery polymer composed of 2,3-dimethylbutadiene and a mixture thereof, or a polymer in which 80% or more of double bonds contained in these rubbery polymers are hydrogenated. Furthermore, these block copolymers may be either linear or branched polymers.

The styrene-based TP used in the present invention
E is a carboxyl group, an acid anhydride group, an acid amide group, in the elastomer portion (soft segment) that constitutes it,
It is particularly preferable to have a group selected from the group consisting of an imide group, a carboxylic acid ester group, an epoxy group, an amino group and a hydroxyl group, from the viewpoint of significantly improving impact resistance. Further, a part of the aromatic ring of the vinyl aromatic hydrocarbon polymer which is the hard segment is substituted with an alkyl group, a halogen atom, a carboxyl group, an acid amide group, a carboxylic acid ester group, an epoxy group, an amino group or a hydroxyl group. It may be

The most preferable styrene-based TPE of the present invention is a block copolymer in which the central block portion is made of polybutadiene having a carboxyl group and the end block portion is made of polystyrene.

The blending amount of the thermoplastic elastomer (B) is
It is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the mixture (A) of the polyamide resin containing the swelling fluoromica mineral and the styrene-based hard polymer. The amount
If the amount is less than 0.01 parts by weight, a molded article having improved impact resistance cannot be obtained, and if the amount exceeds 10% by weight, heat resistance and mechanical strength decrease.

In the thermoplastic resin composition of the present invention, if necessary, a heat stabilizer, a light stabilizer, an antioxidant, a plasticizer, a lubricant, a colorant, a pigment, a foaming agent, a flame retardant, a moldability improving agent. , Additives such as reinforcing agents, lubricants and antistatic agents may be contained.

The resin composition of the present invention is formed into pellets, powder, or another shape using a usual melt-kneading processing apparatus such as an extruder, a Banbury mixer, a kneader, and then injection molding, extrusion molding, blow molding. Various molded products can be processed by a generally known plastic molding method such as vacuum molding, press molding, etc., but a molded product obtained by injection molding is particularly useful.

[0041]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, the raw materials and the measuring methods used in the evaluation of the examples and comparative examples are as follows. (1) Raw material 1. Swelling Fluorine Mica-Based Mineral Talc pulverized to have an average particle size of 2 μm is mixed with fluorinated silica shown in Table 1 having an average particle size of 2 μm in an amount of 20% by weight, Put this in a magnetic crucible and hold it in an electric furnace at 800 ° C for 1 hour.
M-1 and M-2 fluoromica-based minerals were synthesized. As a result of measuring the generated fluoromica-based mineral by the X-ray powder method, the peak corresponding to the thickness 9.2Å of the raw material talc in the c-axis direction disappeared and corresponded to 12 to 16Å indicating the formation of swellable fluoromica-based mineral. A peak was observed.

[0042]

[Table 1]

2. Styrene-based hard polymer Polystyrene (made by Idemitsu Petrochemical Co., Ltd., Idemitsu styrene standard product) and styrene / maleic anhydride copolymer (made by Arcopolymer, Dailark 232) were used. 3. Styrenic TPE A block copolymer consisting of polybutadiene having a carboxyl group in the central block portion and polystyrene in the end block portion (Kraton DX-130 manufactured by Shell Chemical Co., Ltd.).
0) was used.

(2) Measuring method 1. Flexural strength and flexural modulus Measured according to ASTM D-790. 2. Izod impact strength Measured according to ASTM D-256. 3. Heat distortion temperature Measured according to ASTM D-648.

Examples 1 to 4 To 10 kg of ε-caprolactam, 1 kg of water and 400 g of swelling fluoromica mineral (M-1) were blended, and this was put in a reactor having an internal volume of 30 liters, and ε -Caprolactam was polymerized to obtain a nylon 6 resin composition. The polymerization reaction was performed as follows. That is, while stirring,
The mixture was heated to 50 ° C., the pressure was raised to 15 kg / cm ² while gradually releasing steam, and then the pressure was released to normal pressure, followed by polymerization at 260 ° C. for 3 hours. At the end of the polymerization, the nylon 6 resin composition was discharged from the reactor and cut into pellets. 95 pellets of the obtained nylon 6 resin composition
After treatment with hot water at ℃ and scouring, it was vacuum dried. 100 parts by weight of this pellet (relative viscosity 2.5), polystyrene 5
~ 40 parts by weight and Kraton DX-1300 4 parts by weight,
Using a twin-screw extruder (type PCM-45, manufactured by Ikegai Tekko Co., Ltd.), these mixtures were injection-molded at a cylinder temperature of 250 ° C and a mold temperature of 70 ° C to prepare 1 / 8-inch thick test pieces. Then, a physical property test was conducted. Table 2 shows the obtained results.

[0046]

[Table 2]

Comparative Examples 1 to 4 Nylon 6 (relative viscosity 2.5) 100 parts by weight, polystyrene 5
-40 parts by weight and 4 parts by weight of Kraton DX-1300 were mixed, a test piece was prepared in the same manner as in Example 1, and a physical property test was conducted. Table 3 shows the obtained results.

[0048]

[Table 3]

Examples 5 to 8 Test pieces were prepared in the same manner as in Examples 1 to 4 except that Dailark 232 was used instead of polystyrene, and the physical properties were tested. Table 4 shows the obtained results.

[0050]

[Table 4]

Comparative Examples 5 to 8 Test pieces were prepared in the same manner as in Comparative Examples 1 to 4 except that Dailark 232 was used instead of polystyrene, and the physical properties were tested. Table 5 shows the obtained results.

[0052]

[Table 5]

Examples 9-12 Examples 1-4, except that M-2 was used in place of M-1.
A test piece was prepared in the same manner as above, and a physical property test was conducted. Table 6 shows the obtained results.

[0054]

[Table 6]

[0055]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a thermoplastic resin composition which can be formed into a molded article having excellent heat resistance, mechanical strength and impact resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI technical display location C08L 53:02) (72) Inventor Shinichiro Katahira 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Stock Company Central In the laboratory (72) Inventor Izumi Yoshida 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Ltd. Central Research Laboratory

Claims (3)

[Claims] 1. A) (a) (a) swellable fluoromica-based mineral
Polyamide resin containing 01 to 50 wt% 99 to 10 wt% and
(b) A thermoplastic resin composition comprising 0.01 to 10 parts by weight of a thermoplastic elastomer (B) blended with 100 parts by weight of a resin mixture comprising 1 to 90% by weight of a styrene-based hard polymer. 2. The thermoplastic resin composition according to claim 1, wherein the thermoplastic elastomer is a styrene-based thermoplastic elastomer. 3. A styrene-based thermoplastic elastomer having a group consisting of a carboxyl group, an acid anhydride group, an acid amide group, an imide group, a carboxylic acid ester group, an epoxy group, an amino group and a hydroxyl group in the elastomer portion constituting the styrene thermoplastic elastomer. The thermoplastic resin composition according to claim 2, which has a group selected from the following.