JP2001158848A - Thermoplastic elastomer resin composition for powder molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic elastomer having excellent flowability of the molten resin which allows a powder slash molding at lower mold temperatures than that of conventional resins. SOLUTION: This thermoplastic elastomer resin composition comprises a composition obtained by carrying out dynamic crosslinking by using (a) 100 pts.wt. of a block copolymer composed of at least two units of a polymer block A containing an aromatic vinyl compound as a main component and at least one unit of a polymer block B containing a conjugated diene compound as a main component and/or a hydrogenated block copolymer obtained by hydrogenating thereto, (b) 20-300 pts.wt. of a softening agent for a non-aromatic rubber, (c) 10-150 pts.wt. of a peroxide-decomposing type olefin-based resin, (d) 0.01-15 pts.wt. of an unsaturated glycidyl compound, (e) 0.01-15 pts.wt. of an unsaturated carboxylic acid or a derivative thereof, (f) 1-30 pts.wt. of a liquid polybutadiene and (g) 10-2,500 pts.wt. of a thermoplastic polyurethane resin having 10,000-500,000 number-average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermoplastic elastomer resin for powder molding, and more particularly, to a thermoplastic elastomer resin composition having excellent fluidity even in powder slush molding with low shearing force, The present invention relates to a resin granule for powder molding from a composition.

[0002]

2. Description of the Related Art A powder slush molding method is widely used for producing a skin of an inner layer component of an automobile, for example, an instrument panel, a console box and the like. Conventionally, polyvinyl chloride-based resins have been used because a molded article having a soft feel can be obtained by providing a texture or a stitch on the surface of the molded article.

[Problems to be solved by the invention]

In recent years, from the viewpoint of environmental problems, a thermoplastic elastomer or a polyurethane resin has been used instead of the polyvinyl chloride resin. In the powder slush molding method, since the shearing force applied to the resin is small, the molten resin needs to have good fluidity so as to form a uniform thickness over the entire mold. In the molding of (1), sufficient fluidity cannot be obtained unless the mold temperature is set to be considerably higher than that of the polyvinyl chloride resin, for example, about 300 ° C. As a result of repeated heating and cooling of the mold, there is a problem that the mold quickly deteriorates due to metal fatigue. Therefore, a thermoplastic elastomer having a good flowability of a molten resin even at a lower mold temperature is required.

Japanese Patent Application Laid-Open No. Hei 10-310617 discloses a thermoplastic elastomer resin composition containing a polyurethane resin. In the invention described in the publication, each of the resin compositions is subjected to injection molding. The present inventors have conducted experiments and found that the molten resin fluidity of the composition is not satisfactory for powder slush molding applications.

Accordingly, the present inventors have conducted various studies to enhance the flowability of the molten resin. As a result, a powder molding composition having excellent fluidity in powder slush molding by blending a polyurethane resin derived from a polyol having a predetermined molecular weight and having a molecular weight in a predetermined range. Was obtained.

[0006]

That is, the present invention provides at least the following components: (a) at least two polymer blocks A mainly composed of a vinyl aromatic compound and a polymer block B mainly composed of a conjugated diene compound. And / or 100 parts by weight of a hydrogenated block copolymer obtained by hydrogenating the same, and (b)
20 to 300 parts by weight of a softener for non-aromatic rubber, (c) a peroxide-decomposable olefin-based resin, and / or a copolymer containing a peroxide-decomposable olefin-based resin 10 to
150 parts by weight, (d) unsaturated glycidyl compound 0.01
To 15 parts by weight, (e) unsaturated carboxylic acid or its derivative 0.01 to 15 parts by weight, (f) liquid polybutadiene
A composition obtained by subjecting 1 to 30 parts by weight to dynamic crosslinking;
And (g) a thermoplastic polyurethane resin derived from a polyol having a number average molecular weight of 600 to 3,000 and having a number average molecular weight of 10,000 to 500,000, and 10 to 2,500 parts by weight, which is a thermoplastic elastomer resin composition for powder molding. . Component (g) The thermoplastic polyurethane resin has a number average molecular weight of 80
Preferably, it is derived from a polyol of 0 to 2,000 and has a number average molecular weight of 10,000 to 300,000. Further, it is preferable that (g) the thermoplastic polyurethane resin is contained in an amount of 180 to 2500 parts by weight based on 100 parts by weight of the component (a). Furthermore, the present invention provides a thermoplastic elastomer resin composition for powder molding according to any one of the above, which is obtained by molding by an underwater cutting method, and has a long diameter of 400 μm.
The present invention also relates to a granular thermoplastic elastomer resin for powder molding, which has a ratio of major axis to minor axis of from 3: 1 to 1: 1.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component of the resin composition of the present invention will be described. (G) Component Thermoplastic polyurethane resin The resin composition of the present invention comprises (g) a number average molecular weight of 600 to 3,000.
And a number average molecular weight of 10,0
It is characterized by containing from 00 to 500,000 thermoplastic polyurethane resin. By blending such a relatively low molecular weight polyurethane resin, even under a low shear force during powder slush molding, the flowability of the molten resin is good, and the obtained molded article has excellent scratch resistance. Shows sex. The lower limit of the number average molecular weight of the urethane resin is 600,
Preferably 800, the upper limit is 3,000, preferably 2,000
0, and the urethane resin has a number average molecular weight of 10,000 to 500,000, preferably 10,000 to 4
00,000, more preferably 10,000 to 300,000. When the molecular weight of the polyol is less than the lower limit, the scratch resistance and the adhesion to metal are deteriorated, and the solidification rate is reduced, and the moldability is reduced. On the other hand, if you exceed the upper limit,
The fluidity improving effect becomes insufficient. If the molecular weight of the thermoplastic urethane resin is less than the above lower limit, the desired mechanical properties cannot be obtained, and the scratch resistance is poor. On the other hand, when the molecular weight of the thermoplastic urethane resin exceeds the above upper limit value, although excellent in scratch resistance, fluidity is deteriorated, and pinholes are generated in a molded product, and molding processability is deteriorated. The molecular weight in the present invention is a value determined by GPC based on polystyrene having a known molecular weight. Therefore, it should be noted that the values are relative values, not absolute values. In addition, ± 3 depending on GPC conditions such as reference sample, equipment, data processing method, etc.
It should be noted that there can be as much as 0% variation.

As one of the indexes reflecting the molecular weight of the urethane resin, a flow start temperature can be used. The thermoplastic urethane resin in the present invention has a flow start temperature of 120.
150150 ° C., preferably 130-145 ° C. In the present invention, the flow start temperature was measured using a Koka flow tester under the following conditions. Dice: 1mm in diameter x 1mm in length Hold time: 10 minutes Load: 30kg

The thermoplastic polyurethane resin used in the present invention has a molecular weight within the above range.
It may be arbitrary. Typically, a thermoplastic polyurethane resin consisting of a polyol, a diisocyanate, and a chain extender is used. Polyols include polyester polyols, polyester ether polyols, polycarbonate polyols and polyether polyols.

Examples of the polyester polyol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid, and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. A cyclic dicarboxylic acid such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid, or an acid ester or anhydride thereof, and ethylene glycol, 1,3
-Propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5
-Pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, etc.
Or, a polyester polyol obtained by a dehydration condensation reaction with a mixture thereof; a polylactone diol obtained by ring-opening polymerization of a lactone monomer such as ε-caprolactone, and the like.

The polycarbonate polyols include ethylene glycol, 1,3-propylene glycol, 1,2-
Propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8- Examples thereof include those obtained by reacting one or more polyhydric alcohols such as octanediol, 1,9-nonanediol, and diethylene glycol with diethylene carbonate, dimethyl carbonate, diethyl carbonate, and the like.

Examples of the polyester ether polyol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid, and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. Alicyclic dicarboxylic acids, such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid, or acid esters or acid anhydrides thereof, and glycols such as diethylene glycol or propylene oxide adducts; or Products obtained by a dehydration condensation reaction with these mixtures are mentioned.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol obtained by polymerizing cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran, respectively, and copolyethers thereof. Among the above various polyols, polyether polyols are preferred from the viewpoint of hydrolysis resistance.

As the isocyanate, for example, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate Isocyanate (XDI), hydrogenated XD
I, triisocyanate, tetramethylxylene diisocyanate (TMXDI), 1,6,11-undecane triisocyanate, 1,8-diisocyanatomethyloctane, lysine ester triisocyanate, 1,
Examples include 3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, and the like. Among them, 4,4'-diphenylmethane diisocyanate (M
DI) is preferably used.

As the chain extender, a low molecular weight polyol is used. For example, ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, 1,4-cyclohexanediene Examples include aliphatic polyols such as methanol and glycerin, and aromatic glycols such as 1,4-dimethylolbenzene, bisphenol A, and ethylene oxide or propylene oxide adducts of bisphenol A.

The amount of component (g) is 100 parts (a).
10 to 2500 parts by weight, preferably 180 to 250 parts by weight
0 parts by weight. If the amount is less than 10 parts by weight, the effects of the present invention will not be sufficiently exhibited. On the other hand, if it exceeds 2500 parts by weight,
The flexibility of the obtained elastomer composition is reduced, and there is no great difference from the polyurethane polymer alone. By blending the component (g), the fluidity of the molten resin is improved, and the resulting molded article is significantly improved in scratch resistance and oil resistance. Furthermore, if the elastomer containing the polyurethane resin is used as a skin of an automobile interior part comprising an olefin core material and an intermediate foam layer of urethane foam,
Can be recycled by crushing all at once.

(A) Component Block Copolymer Component (a) in the present invention comprises at least two polymer blocks A mainly composed of a vinyl aromatic compound and at least two polymer blocks B mainly composed of a conjugated diene compound. A block copolymer comprising at least one of them, a block copolymer obtained by hydrogenating the block copolymer, or a mixture thereof, for example, ABA, BABA, ABA- BA
And a hydrogenated product of a vinyl aromatic compound-conjugated diene compound block copolymer having such a structure. The above (hydrogenated) block copolymer (hereinafter, the (hydrogenated) block copolymer means a block copolymer and / or a hydrogenated block copolymer) is obtained by adding a vinyl aromatic compound to 5 to 60 parts. % By weight, preferably 20 to 50% by weight. The polymer block A mainly composed of a vinyl aromatic compound is preferably composed of only a vinyl aromatic compound,
More than 0% by weight, preferably 70% by weight or more, and a (hydrogenated) conjugated diene compound (hereinafter, a (hydrogenated) conjugated diene compound is a conjugated diene compound and / or a hydrogenated conjugated diene compound. (Means a diene compound)
And a copolymer block. The polymer block B based on a (hydrogenated) conjugated diene compound preferably consists only of the (hydrogenated) conjugated diene compound or has a (hydrogenated) conjugated diene compound of 50%.
It is a copolymer block of more than 70% by weight, preferably 70% by weight or more, and a vinyl aromatic compound. A polymer block A mainly composed of these vinyl aromatic compounds,
In each of the polymer blocks B mainly composed of a (hydrogenated) conjugated diene compound, the distribution of the vinyl compound or the (hydrogenated) conjugated diene compound in the molecular chain is random, tapered (monomer along the molecular chain). Component may be increased or decreased), partially block-like, or any combination thereof. When there are two or more polymer blocks A mainly containing a vinyl aromatic compound or two or more polymer blocks B mainly containing a (hydrogenated) conjugated diene compound, they have different structures even if they have the same structure. There may be.

(Hydrogenated) As the vinyl aromatic compound constituting the block copolymer, for example, one or more selected from styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene and the like are selected. Of which styrene is preferred. Further, as the conjugated diene compound, for example, one or more kinds are selected from butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like.
Isoprene and combinations thereof are preferred.

The microstructure of the polymer block B mainly composed of a conjugated diene compound can be arbitrarily selected.
In the butadiene block, the 1,2-microstructure is preferably from 20 to 50%, particularly preferably from 25 to 45%. In the polyisoprene block, 70% of the isoprene compound
-100% by weight has a 1,4-microstructure and at least 9 aliphatic double bonds based on the isoprene compound.
Those in which 0% is hydrogenated are preferred.

The weight average molecular weight of the (hydrogenated) block copolymer of the present invention having the above structure is preferably 5,000 to 1,500,000, more preferably 1 to 1.
0000 to 550,000, more preferably 10
0000 to 550,000, particularly preferably 100,
The range is from 000 to 400,000. Molecular weight distribution (ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (M
w / Mn)) is preferably 10 or less, more preferably 5 or less.
Or less, more preferably 2 or less. The molecular structure of the (hydrogenated) block copolymer may be linear, branched, radial, or any combination thereof.

Numerous methods have been proposed as methods for producing these block copolymers. Representative methods include, for example, a method described in Japanese Patent Publication No. 40-23798, which uses a lithium catalyst or a Ziegler catalyst. It can be obtained by performing block polymerization in an inert solvent using a type catalyst. By hydrogenating the block copolymer obtained by the above method in the presence of a hydrogenation catalyst in an inert solvent, a hydrogenated block copolymer is obtained.

Specific examples of the (hydrogenated) block copolymer include SBS, SIS, SEBS, and SEPS. In the present invention, a particularly preferred (hydrogenated) block copolymer is a polymer block A mainly composed of styrene, and mainly composed of isoprene, and 70 to 100% by weight of isoprene has a 1,4-micro structure, And at least 90 of aliphatic double bonds based on the isoprene
% Is a hydrogenated block copolymer having a weight average molecular weight of 5,000 to 550,000 and a polymer block B to which hydrogen has been added. More preferably, 90 to 100% by weight of isoprene is the above hydrogenated block copolymer having a 1,4-microstructure.

(B) Component Softener for Non-Aromatic Rubber As the component (b) in the present invention, a non-aromatic mineral oil or a liquid or low molecular weight synthetic softener can be used. Mineral oil softeners used for rubber are
A mixture of an aromatic ring, a naphthene ring, and a paraffin chain in which the number of carbon atoms in the paraffin chain accounts for 50% or more of the total number of carbon atoms is called a paraffinic system.
Those having 30 to 40% of naphthenic ring carbon atoms are naphthenic,
Those having an aromatic carbon number of 30% or more are called aromatics and are distinguished.

The mineral oil-based rubber softeners used as component (b) in the present invention are paraffinic and naphthenic based in the above category. The use of an aromatic softening agent is not preferred because its use makes the component (a) soluble and inhibits the cross-linking reaction so that the desired improvement in physical properties cannot be achieved. As the component (b), a paraffin-based component is preferable, and a paraffin-based component having less aromatic ring components is particularly preferable.

These non-aromatic rubber softeners have a dynamic viscosity at 37.8 ° C. of 20 to 500 cS.
t, pour point is -10 to -15 ° C, flash point (COC) is 1
Indicates 70 to 300 ° C.

The amount of component (b) is 100 parts
The lower limit is 20 parts by weight, preferably 4 parts by weight.
0 parts by weight, more preferably 80 parts by weight, most preferably 100 parts by weight, and the upper limit is 300 parts by weight, preferably 200 parts by weight, more preferably 170 parts by weight.
If the amount exceeds the above upper limit, bleed-out of the softener is likely to occur, which may give tackiness to the final product, and also deteriorates the mechanical properties of the molded product. On the other hand, if the amount is less than the lower limit, the moldability of the obtained composition will be poor. Component (b) has a weight average molecular weight of 100 to 2,000.
00 is preferred.

Component (c) peroxide decomposable olef
Component- based resin and / or copolymer containing the same The component (c) in the present invention has an effect of improving the dispersion of the component (a) in the obtained composition and improving the appearance of a molded article. The amount of the component (c) is 100 parts (a).
The lower limit is 10 parts by weight, preferably 25 parts by weight, and the upper limit is 150 parts by weight, preferably 100 parts by weight.
Parts by weight. If the amount is less than the lower limit, the moldability of the obtained elastomer composition is poor, while if it exceeds the upper limit, the flexibility and rubber elasticity of the obtained elastomer composition are deteriorated.

The peroxide-decomposable olefin resin suitable as the component (c) in the present invention is rrrr / l in pentad fraction by ¹³ C-nuclear magnetic resonance absorption method.
-Mmmm is 20% or more, and the melting peak temperature (Tm) determined by differential scanning calorimetry is 150 ° C.
The melting enthalpy (ΔHm) is 100 J / g or less. Preferably, Tm is 150 ° C to 167
C and ΔHm are in the range of 25 mJ / mg to 83 mJ / mg. The crystallinity can be estimated from Tm and ΔHm. When Tm and ΔHm are out of the above range,
The rubber elasticity at 100 ° C. or higher of the obtained elastomer composition is not improved.

Examples of the peroxide-decomposable olefin resin include high-molecular-weight homopolypropylene, for example, isotactic polypropylene and propylene and a small amount of other α-olefins, for example, ethylene, 1-butene, 1-hexene, 4-methyl. Copolymers with -1-pentene and the like are preferred. The MFR of the resin (ASTM-D-1238, L
Condition, 230 ° C.) is preferably 0.1 to 10 g / 10
Min, more preferably 3 to 8 g / 10 min.

If the MFR of the peroxide-decomposable olefin resin is less than 0.1 g / 10 minutes, the moldability of the obtained elastomer will be reduced. If the MFR exceeds 10 g / 10 minutes, the rubber elasticity of the obtained elastomer composition will be reduced. Is not preferable because it deteriorates.

In addition to the peroxide-decomposable olefin resin, the number average molecular weight (Mn) is 25,000 or more, and the weight average molecular weight (Mw) and the number average molecular weight (M
n) and a boiling heptane-soluble polypropylene having a ratio (Mw / Mn) of 7 or less and a melt index of 0.1 to 4 g.
Peroxide decomposable olefin resin composed of / 10 minute boiling heptane-insoluble polypropylene, boiling heptane-soluble polypropylene having an intrinsic viscosity [η] of 1.2 dl / g or more, and an intrinsic viscosity [η] of 0.5 to 9.0 dl. / G
A peroxide decomposable olefin-based resin composed of a boiling heptane-insoluble polypropylene of the formula (I) can also be used.

Component (d) the unsaturated glycidyl compound or
The oil resistance and abrasion resistance of the resin composition are improved by blending a derivative unsaturated glycidyl compound or a derivative thereof and subjecting it to dynamic crosslinking. A glycidyl compound having an unsaturated group capable of copolymerizing with an olefin and a glycidyl group in the molecule is preferably used, and glycidyl methacrylate (GMA) is particularly preferably used. The unsaturated glycidyl compound or a derivative thereof is preferably used to modify polyethylene and polypropylene. That is, the soft component of the hydrogenated block copolymer in the component (a) and the component (c)
Of the peroxide-decomposable olefin-based resin and / or a copolymer containing the same.

The amount of component (d) is 100 parts (a)
The upper limit is 15 parts by weight, preferably 10 parts by weight, and the lower limit is 0.01 parts by weight, preferably 0.1 part by weight.
Parts by weight, particularly preferably 3 parts by weight. If the ratio exceeds the above upper limit, not only the thermal deformation resistance and mechanical properties of the composition are deteriorated, but also the effect of improving the compatibility of the component (g) in the composition is not recognized.

Component (e) unsaturated carboxylic acid or derivative thereof
The oil resistance and abrasion resistance of the resin composition are improved by blending the conductive unsaturated carboxylic acid or its derivative and subjecting it to dynamic crosslinking. Preferably acrylic acid, methacrylic acid, maleic acid, dicarboxylic acids or derivatives thereof such as acids, halides,
Examples include amides, imides, anhydrides, and esters. Particularly preferably, maleic anhydride (MAH) is used.
Preferably, polypropylene or the like is modified with the unsaturated carboxylic acid or derivative thereof. That is, it is considered that the soft component of the hydrogenated block copolymer in the component (a) and the peroxide-decomposable olefin resin of the component (c) and / or the copolymer containing the same are modified.

The amount of component (e) is 100 parts (a)
The upper limit is 15 parts by weight, preferably 10 parts by weight, and the lower limit is 0.01 parts by weight, preferably 0.1 part by weight.
Parts by weight, particularly preferably 5 parts by weight. If the amount exceeds the upper limit, severe yellowing occurs in the composition, and not only the heat deformation resistance and mechanical properties are deteriorated, but also the effect of improving the compatibility of the component (g) when the component (g) is blended. Will not be recognized.

Component (f) Liquid polybutadiene Liquid polybutadiene has a main chain fine structure of vinyl 1,2.
-A liquid polymer which is transparent at room temperature and comprises a trans-linked type, a trans 1,4-linked type, and a cis 1,4-linked type.
Here, the vinyl 1,2-linkage is preferably 30% by weight or less, and if the vinyl 1,2-linkage exceeds 30% by weight, the low-temperature properties of the obtained composition are unfavorably deteriorated.

The number average molecular weight of the liquid polybutadiene is:
The upper limit is preferably 5,000, more preferably 4,000.
0, and the lower limit is preferably 1,000, more preferably 3,000. If the amount is less than the lower limit, the heat-deformation resistance of the obtained composition decreases, and if it exceeds the upper limit, the compatibility of the obtained composition decreases.

Further, the liquid polybutadiene is preferably a copolymerizable compound having one or more groups selected from an epoxy group, a hydroxyl group, an isocyanate group and a carboxyl group. Among them, those having a hydroxyl group and a copolymerization-reactive unsaturated double bond are particularly preferred. Commercially available products include, for example, R-45H manufactured by Idemitsu Petrochemical Co., Ltd.
T (trademark).

The amount of the component (f) is 100 parts (a)
The upper limit is 30 parts by weight, preferably 10 parts by weight, and the lower limit is 1 part by weight, preferably 3 parts by weight with respect to parts by weight. If the amount is less than the lower limit, the effect of addition is not recognized. If the amount exceeds the upper limit, the mechanical properties of the composition deteriorate.

Organic peroxide In the dynamic crosslinking in the present invention, an organic peroxide is used. As the organic peroxide, for example, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-
Butylperoxy) hexane, 2,5-dimethyl-2,
5-di (tert-butylperoxy) hexyne-3
1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane,
n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxy Examples thereof include isopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butylcumyl peroxide.

Of these, 2,5-dimethyl-2,5-di- (te) is preferred in terms of odor, coloring and scorch stability.
Most preferred are rt-butylperoxy) hexane, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3,1,3-bis (tert-butylperoxyisopropyl) benzene.

The amount of peroxide to be added depends on the amount of component (a) 1
For 100 parts by weight, the lower limit is 0.1 part by weight, preferably
0.2 parts by weight, more preferably 0.6 parts by weight, and the upper limit is 4.0 parts by weight, preferably 3.5 parts by weight, more preferably 3.0 parts by weight. If it is less than the lower limit, the required crosslinking cannot be obtained. On the other hand, if it exceeds the above upper limit, crosslinking proceeds too much,
Dispersion of the cross-linked product becomes worse.

Crosslinking Aid In the present invention, a crosslinking aid is preferably used for dynamic crosslinking. The range of the added amount of the crosslinking assistant used is
The lower limit is 0.1 part by weight, preferably 1.0 part by weight, more preferably 2.0 parts by weight, and the upper limit is 10.0 parts by weight based on 100 parts by weight of component (a) at the time of addition. Parts, preferably 8.0 parts by weight, more preferably 6.0 parts by weight. If it is less than the lower limit, the required crosslinking cannot be obtained. On the other hand, when the ratio exceeds the upper limit, the crosslinking efficiency decreases. The addition amount of the crosslinking aid is preferably about 1.0 to 3.0 times the peroxide addition amount.

In addition to the above components, the resin composition of the present invention may contain a releasing agent such as stearic acid and silicone oil, a lubricant such as polyethylene wax, a pigment, alumina and the like as long as the object of the present invention is not impaired. Inorganic fillers, antioxidants, foaming agents (organic and inorganic), flame retardants (hydrated metal compounds, red phosphorus, ammonium polyphosphate, antimony, silicone) and the like.

The resin composition of the present invention can be produced, for example, by the following steps. First, a crosslinking agent is added to components other than the component (g) and kneaded under heating. Preferably, a crosslinking aid is also added. As the kneading method, a method usually used for rubber, plastics and the like can be used satisfactorily. For example, a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, various kneaders and the like are used. By this step, a composition in which each component is uniformly dispersed can be obtained.

Next, the component (g) is added to the composition obtained in the above step and kneaded. The kneading can be generally performed using a single-screw extruder, a twin-screw extruder, a roll, a Banbury mixer, various kneaders, or the like. In this step, the cross-linking reaction is completed at the same time as the dispersion of each component further proceeds. Conveniently, the step of side-feeding component (g) and subjecting it to dynamic crosslinking is carried out continuously.

As a kneading method, it is preferable to use a twin-screw extruder or a Banbury mixer having an L / D of 47 or more, since all the steps can be performed continuously. In addition, for example, when kneading with a twin-screw extruder, the rotation speed of the screw is 80 to 350 rpm, preferably 80 to 200 rpm.
When the reaction is performed under the condition of m, dispersion of each component is good, and a material having good physical properties can be obtained.

In the powder slush molding method,
It is necessary that the powder itself has excellent fluidity so that the powder adheres uniformly to a mold having a complicated shape and the excess is easily removed. The present inventors have found that by replacing the thermoplastic elastomer resin with conventional powders and forming granular bodies of a predetermined shape and size, the fluidity can be dramatically improved, and a patent application has been filed. (Japanese Patent Application No. 11-139056)
issue). By making the resin composition of the present invention also a granular material,
The powder fluidity when attaching the resin to the mold is improved.

The granules are slightly elongated granules. Since it is substantially spherical, good fluidity is obtained. The major axis of the grain is obtained by measuring the longest axis (hereinafter, referred to as “major axis”) in a photographic image at a magnification of about 20 to 30 times. The range of the major axis can be appropriately determined according to the shape of the mold, the resin component, and the like. It suffices that voids are not formed when flowing into a mold and small enough to flow into details. However, if it is too small, it is thought that there is no advantage in flowability or handling as compared with conventional powders. 400μm for powder slush molding of automotive interior parts
m or less, more preferably 360 μm or less. In the photographic image, the ratio of the major axis to the shortest in the direction perpendicular to the major axis (hereinafter referred to as “minor axis”) is 3: 1 or less, preferably 2: 1 or less, and more preferably 1.5: 1.
It is as follows.

The above granular material can be produced by an underwater cutting method. The underwater cutting method is a method in which a thermoplastic elastomer composition is extruded into water from an extruder die hole, and the extruded resin is cut by a blade provided very close to the die to obtain a granular material. In the present invention, the extruder die is, for example, provided with an underwater pelletizing system (Underwater Pelting System manufactured by Gala).
letting Systems) to cool and cut immediately after the resin is extruded. In order to obtain a granular material having the size of the present invention, the diameter of the discharge opening of the die is 3 mm or less, preferably 1.
It is 0 mm or less, more preferably 0.3 mm or less. Also, the discharge speed of the thermoplastic elastomer composition per discharge port of the die, when the discharge diameter of the die is 0.3 mm,
Preferably it is 10-250 g / h. In order to prevent blocking, the temperature of the water is usually 5 to 80 ° C, preferably 5 to 40 ° C. Further, an anti-blocking agent may be added to water. As a method other than the underwater cutting method, there is a method of spraying or cooling a molten resin by a spray or an atomizer to form granules.

[0051]

The present invention will be described in detail below with reference to examples and comparative examples. The amounts in the table mean parts by weight unless otherwise specified.

Resin used component (a): hydrogenated block copolymer (SEPS) Septon 4077 manufactured by Kuraray Co., Ltd. Styrene content: 30% by weight Isoprene content: 70% by weight Number average molecular weight: 260,000 weight average Molecular weight: 320,000 Molecular weight distribution: 1.23 Hydrogenation rate: 90% or more Component (b): Non-aromatic rubber softener Diana Process Oil PW-90 manufactured by Idemitsu Kosan Co., Ltd. Type: paraffinic oil Weight average molecular weight: 540 Content of aromatic component: 0.1% or less Component (c): peroxide-decomposable olefin resin PP CJ700 manufactured by Mitsui Petrochemical Company Type: PP MFR: 7 g / 10 min Crystallinity: Tm 166 ° C. Hm 82 mJ / mg Component (d): Glycidyl methacrylate Kanto Chemical Co., Ltd. Component (e): Maleic anhydride Kanto Chemical Co., Ltd. Component (f): liquid polybutadiene R-45HT (trade name) manufactured by Idemitsu Petrochemical Industry Co., Ltd. A hydroxyl group (acrylic primary) as a functional group and a copolymerizable unsaturated double bond (1,4 bond: 80%) )have. Number average molecular weight: 2800 Component (g): thermoplastic polyurethane resin (TPU) Various thermoplastic polyurethane resins derived from polyols having various molecular weights shown in Table 2 were used. Organic peroxide: Peroxa 25B (2,5-dimethyl- manufactured by NOF Corporation)
2,5-di (t-butyl peroxide) hexane) Crosslinking aid: NK ester IND (2-methyl- manufactured by Shin-Nakamura Chemical Co., Ltd.)
1,8-octanediol dimethacrylate (85
%), 1,9-nonanediol dimethacrylate (15%
%) Mixture) Method for measuring molecular weight The molecular weight was measured by GPC under the following conditions, and the molecular weight was determined using polystyrene as a standard. Eluent: dimethylformamide (DMF) Flow rate: 1.0 ml / min Detector: RI Column: Shodex KD-80M x 3 Column temperature: 40 ° C Viscosity measurement At 200 ° C, Capillograph 1B manufactured by Toyo Seiki Seisaku-sho (Capillary diameter) 1mm, length 20mm, shear force 6.
At 08 sec ^-1 ), the viscosity was measured. Tensile strength, elongation, 100% modulus JIS K 7161 The sample was a 2 mm thick injection molded sheet, and the test piece was a No. 3 dumbbell. The surface of the test piece was rubbed 1200 times using a campus cloth (Kanakin No. 3) while applying a load of 100 g from above, and the surface of the test piece was visually observed for scratches, and the following criteria were applied. evaluated. OK: Almost no scratches and no stain on the campus cloth. NG: The scratch was remarkable, or the campus cloth was stained. Hardness After 15 seconds, the hardness was measured according to JIS K 6253. When the molded product was removed from the mold for release, the evaluation was made according to the following criteria. ：: The mold could be released from the mold without any problem, and no deformation was observed. ×: A part of the molded product remained in the mold, and / or deformation of the removed molded product was observed.

Preparation of Resin Composition At the component ratio shown in Table 1, components (a) to (f) were first kneaded with a twin-screw extruder, peroxide and a crosslinking assistant were added, and a kneading temperature of 200 ° C. Dynamic crosslinking treatment was performed at a screw rotation of 350 rpm and an extruder discharge rate of 20 kg / hour. Next, Comparative Example 5
And kneaded by side-feeding the component (g). Underwater Pelle from Gala Industries, Inc. at the exit of the extruder
A granular sample having a major axis of about 0.3 mm was prepared using the tizing system. In Comparative Example 6, a pellet of the component (g) was formed into a granular sample. Various test pieces were prepared using each of the obtained granular material samples, and each evaluation was performed. Table 2 shows the obtained results.

[Table 1]

[Table 2] As shown in Table 2, the resin compositions of Examples 1 and 2 according to the present invention have a lower viscosity under low shear than the compositions of Comparative Examples 1 to 4, and are excellent in fluidity. Further, the molded articles obtained from the compositions of Examples 1 and 2 were excellent in scratch resistance. On the other hand, the compositions of Comparative Example 1 having a high molecular weight of the polyol and Comparative Example 4 having a high molecular weight of the urethane resin were all inferior in fluidity. The polyol of Comparative Example 4 is the same as the urethane resin used in JP-A-10-310617 by the present inventors. Further, the compositions of Comparative Examples 2 and 3 in which the molecular weight of the polyol was lower than the range of the present invention were inferior in scratch resistance. The elastomer containing no urethane resin (Comparative Example 5) was inferior in both fluidity and scratch resistance. In the case of only the urethane resin (Comparative Example 6), although the fluidity of the resin was excellent, the solidification rate was slow and the molding processing time was long, and the obtained molded article was very hard and had a poor touch. there were.

[0054]

As described above, since the resin composition of the present invention contains a thermoplastic polyurethane resin having a specific molecular weight range, the fluidity of the resin is improved and powder molding can be performed at a low molding die temperature. Becomes possible. Moreover, the obtained molded article has excellent scratch resistance while having a soft touch.

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Claims (4)

[Claims] A block copolymer comprising at least the following components: (a) at least two polymer blocks A mainly composed of a vinyl aromatic compound and at least one polymer block B mainly composed of a conjugated diene compound. Polymer and / or hydrogenated block copolymer 10 obtained by hydrogenating the same
0 parts by weight, (b) 20 to 300 parts by weight of a softening agent for non-aromatic rubber, (c) a peroxide-decomposable olefin-based resin, and / or a copolymer containing a peroxide-decomposable olefin-based resin 10 to 150 Parts by weight, (d) 0.01 to 15 parts by weight of an unsaturated glycidyl compound, (e) 0.01 to 15 parts by weight of an unsaturated carboxylic acid or a derivative thereof, and (f) 1 to 30 parts by weight of a liquid polybutadiene. A composition obtained by crosslinking, and (g) a polyol having a number average molecular weight of 10,000 to 50, which is derived from a polyol having a number average molecular weight of 600 to 3,000.
A thermoplastic polyurethane resin composition for powder molding, comprising 10 to 2500 parts by weight of a thermoplastic polyurethane resin of 000. 2. Component (g) a thermoplastic polyurethane resin,
The thermoplastic elastomer resin composition for powder molding according to claim 1, wherein the thermoplastic elastomer resin composition is derived from a polyol having a number average molecular weight of 800 to 2,000 and has a number average molecular weight of 10,000 to 300,000. 3. The thermoplastic elastomer for powder molding according to claim 1, wherein (g) the thermoplastic polyurethane resin is contained in an amount of 180 to 2500 parts by weight based on 100 parts by weight of the component (a). Resin composition. 4. The long diameter obtained by molding the thermoplastic elastomer resin composition for powder molding according to any one of claims 1 to 3 by an underwater cutting method, wherein the long diameter is 400 μm.
Thermoplastic elastomer resin granules for powder molding having the following ratio and the ratio of the major axis to the minor axis is from 3: 1 to 1: 1.