JP3101400B2 - Silicone-modified styrene-based thermoplastic elastomer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silicone-modified styrene-based thermoplastic elastomer and a method for producing the same.
More specifically, the present invention relates to a silicone-modified styrene-based thermoplastic elastomer having improved blocking properties, a method for producing the resin, and a molded article produced from the resin.

[0002]

2. Description of the Related Art A styrene-based thermoplastic elastomer has a polystyrene block as both end blocks and a block such as a polybutadiene block, a polyisoprene block or a polyethylene / polybutylene block as an intermediate block. Since they are incompatible, the polystyrene blocks are uniformly dispersed in the molecule and are linked to each other by the intermediate block, and there is no chemical crosslinking.However, the polystyrene block fixes the end of the intermediate block, and the physical crosslinking network Thus, at room temperature, the rubber exhibits rubber elasticity similar to that of the vulcanized rubber, and the polystyrene block is melted by heating to exhibit thermoplasticity. For this reason, styrene-based thermoplastic elastomers have processing advantages (no need for a mastication step, no vulcanization step, are soluble in a wide range of solvents, have low viscosity, and can be processed in the same manner as general thermoplastics. Compatibility with various types of compounds, easy compounding, etc.), physical properties (high strength, high elasticity, low temperature properties, acid resistance, alkali resistance,
Ozone resistance, oxidation resistance, ultraviolet resistance, heat resistance, etc.) and are used in a wide range of fields.

[0003] However, styrene-based thermoplastic elastomers include raw material pellets and various molded products produced therefrom cause blocking between the pellets or between products, so that the raw material pellets have poor fluidity or are removed from the packaging bag. There are problems such as difficulty in handling the product due to difficulty in bridging in the storage hopper, and inconvenience in processes such as storage, distribution, molding and use.

[0004] As described above, styrene-based thermoplastic elastomers have excellent physical properties, but are severely blocked. To solve this problem, a method of blending or coating a wax has conventionally been adopted. Is undesirable because it bleeds on the surface of the molded article or impairs the physical properties of the molded article.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such a situation, and has improved the blocking property without using a wax while maintaining excellent physical properties of a styrene-based thermoplastic elastomer. An object is to provide a styrene-based thermoplastic elastomer.

[0006]

The present inventors have conducted a number of experiments on the combination of a styrene-based thermoplastic elastomer and another polymer. As a result, the above-mentioned problems were found when blending with a specific polymer and heating and kneading. The present inventors have found out that they can be solved and completed the present invention.

That is, the present invention relates to (A) the following formula I based on 100 parts by weight of a styrene-based thermoplastic elastomer. (Wherein, R ¹ represents an aliphatic unsaturated group, R ² represents an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated group, and a
And b are the following conditions: 0 ≦ a <1, 0.5 <b <3, 1
1 to 500 parts by weight of an organopolysiloxane represented by <a + b <3), (B) 0.1 to 10 parts by weight of a polyfunctional monomer, and (C) 0.0 of an organic peroxide.
The present invention relates to a method for producing a silicone-modified styrene-based thermoplastic elastomer, comprising heating and kneading a composition obtained by adding 0.5 to 1 part by weight.

[0008] The present invention also relates to a silicone-modified styrenic thermoplastic elastomer produced by the above method and a molded article produced from the resin. In the present invention, the molded article is not particularly limited, but is a sheet, a film, a tube, a plate, a rod, or another shape, and is a medical or food product such as a gasket for a syringe, a milk tube, a vending machine tube, a packing and Automobile accessories such as stoppers, front end grills, bumper end caps, side moldings, crash panels, steering wheel covers, connectors for electrical systems, gaskets, grommets, heat duct connectors, etc., electric wire coatings such as battery cable jackets, welding Cable jackets, automotive primer wires, appliance wires, flexible cords, connectors, plugs and wiring in equipment, etc., as well as agricultural and waterproof sheets, daily necessities, sporting goods, leisure goods, health goods,
Civil engineering construction supplies, marine and marine supplies, aerospace supplies, textile and textile supplies, sanitary supplies, and other various molded products.

In the present invention, the styrene-based thermoplastic elastomer is obtained by copolymerizing styrene and butadiene by anionic polymerization, cationic polymerization, coordination polymerization, radical polymerization, solution polymerization, emulsion polymerization, or the like. It means a block copolymer or a polymer obtained by hydrogenating these to eliminate unsaturated double bonds in a polymer chain. Specific examples include those having the following trade names: Tufprene A (a styrene-butadiene linear block copolymer manufactured by Asahi Kasei Kogyo), Sorbrene T-411 (a styrene-butadiene block copolymer manufactured by Nippon Elastomer), Kraton D -1101 (manufactured by Shell Chemical Co., styrene-butadiene-styrene block copolymer) and the like, and tuftec (manufactured by Asahi Kasei Corporation) obtained by hydrogenating them.
Clayton G (manufactured by Shell Chemical), Lavalon (manufactured by Mitsubishi Yuka) and the like. These styrenic thermoplastic elastomers
Part of styrene may be substituted with α-methylstyrene, vinyltoluene, pt-butylstyrene, etc. Similarly, part of butadiene may be substituted with isoprene, 1,3-pentadiene, 2,3-dimethyl- It may be substituted with 1,3-butadiene or the like.

The organopolysiloxane used in the present invention is represented by the above formula I. In the above, R ¹ is exemplified by vinyl, allyl, acryl, methacryl, etc., and R ² is represented by R ^2. Alkyl groups such as methyl group, ethyl group and propyl group, aryl groups such as phenyl group and tolyl group, cycloalkyl groups such as cyclohexyl group and cyclobutyl group, and partially hydrogen atoms bonded to carbon atoms of these hydrocarbon groups. Examples thereof include a group substituted with a halogen atom, a cyano group, a mercapto group and the like, and these may be the same or different combinations thereof.

In the above formula I, a is 0 or more than 0 and less than 1. This range is because if a is 1 or more, the molded article produced by the present invention becomes too hard. a is preferably 0.0004 to 0.06.

In the above formula I, b is greater than 0.5 and less than 3. If the range is 0.5 or less, it is difficult to knead the composition of the present invention, and the processability is inferior. If the range is 3 or more, the molded article produced by the present invention becomes too hard, which is undesirable. b is preferably 1 to 2.

The molecular structure of the organopolysiloxane in the present invention may be any of linear, branched, cyclic, network, and three-dimensional networks, as long as it is represented by the above formula I.

As such an organopolysiloxane, there can be mentioned, for example, a so-called silicone gum stock which is commercially available as a tear strength improving agent for silicone rubber. In addition, the linear organopolysiloxane used in the present invention has a general formula: (Wherein, R represents an unsubstituted or substituted monovalent hydrocarbon group,
n represents a number of 10 or more), and there is one generally called silicone oil.

R in the above formula is a group selected from an alkyl group, an aryl group and a hydrogen atom, and is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group,
Representative examples are an i-butyl group, a t-butyl group, a phenyl group and a hydrogen atom. All the Rs in the molecule may be the same, some Rs may be different groups, and some of the Rs may be vinyl groups or hydroxyl groups.

N is greater than or equal to 10 and 100 to 10
00 is preferred. If n is less than 10, kneading with the styrene-based thermoplastic elastomer becomes difficult.

The viscosity at 23 ° C. of the organopolysiloxane polymer represented by the above formula I used in the present invention is preferably 10 CS or more, more preferably 10 ³ to 10 ⁶ CS. When the viscosity is lower than 10 CS, it is difficult to knead by heating, and the organopolysiloxane polymer may seep out from the surface of the molded article.

In the present invention, the polyfunctional monomer is an organic compound having two or more vinyl groups, allyl groups, (meth) acrylate groups and the like in a molecule, such as diallyl phthalate (DAP), triallyl isocyanurate (TAI).
C), triallyl cyanurate (TAC), tetraallyloxyethane (TAE), divinylbenzene (DV
B), trimethylolpropane trimethacrylate (TMPTMA), triethylene glycol dimetharylate (TEGDMA), ethylene glycol dimetharylate (EGDMA), the following formula: CH ₂ ＣＨCH (C
H ₂ ) _y is an organic compound selected from alkadienes and the like represented by CH ＝ CH ₂ (where y represents an integer of 1 to 30).

Examples of the alkadiene include 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-decadiene, 1,10-undecadiene,
1,11-dodecadienes, 1,12-tridecadienes,
Examples thereof include 1,13-tetradecadiene, 1,14-pentadecadiene, 1,15-hexadecadiene, 1,16-heptadecadiene, and 1,17-octadecadiene.

The use of the polyfunctional monomer enables the reaction between the styrenic thermoplastic elastomer and the organopolysiloxane to proceed in a short time.

The organic peroxide which can be used in the present invention preferably has a decomposition temperature of 100 to 220 ° C. with a half-life of 10 minutes, ie, a half-life (Tp) of 100 to 220 ° C. for 10 minutes. Examples thereof include the following (where the decomposition temperature (° C.) is shown in parentheses): t-butylperoxyisopropyl carbonate (135), t-butylperoxylaurate (140), 2,5- Dimethyl-2,5-di (benzoylperoxy) hexane (140), t-butylperoxyacetate (140), di-t-butyldiperoxyphthalate (140), t-butylperoxymaleic acid (140), cyclohexanone peroxide ( 1
45), t-butyl peroxybenzoate (14
5), dicumyl peroxide (150), 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (155), t-butylcumyl peroxide (15)
5), t-butyl hydroperoxide (158), di-
t-butyl peroxide (160), 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3
(170), di-isopropylbenzene hydroperoxide (170), p-menthane hydroperoxide (1
80), 2,5-dimethylhexane-2,5-dihydroperoxide (213).

In the present invention, the amount of the organopolysiloxane is 1 to 500 parts by weight based on 100 parts by weight of the styrene thermoplastic elastomer. If the amount is less than 1 part by weight, blocking resistance does not appear, and if it exceeds 500 parts by weight, not only the moldability of the modified styrene-based thermoplastic elastomer deteriorates, but also the excellent properties of the styrene-based thermoplastic elastomer are undesirably impaired. .

The amount of the polyfunctional monomer is 0.1 to 1 with respect to 100 parts by weight of the styrene thermoplastic elastomer.
0 parts by weight. If the amount is less than 0.1 part by weight, the reaction time between the styrene-based thermoplastic elastomer and the organopolysiloxane is prolonged, and the use of more than 10 parts by weight is not economical because the effect of accelerating the reaction is saturated.

Further, the amount of the organic peroxide is 0.005 to 100 parts by weight of the styrene thermoplastic elastomer.
１1 part by weight. If the amount is less than 0.005 parts by weight, the modification reaction hardly occurs. Even if the amount is more than 1 part by weight, the reaction effect is hardly improved. Is undesirable.

The silicone-modified styrenic thermoplastic elastomer of the present invention may contain commonly used resin additives such as antioxidants, lubricants, various organic and inorganic pigments, UV inhibitors, dispersants, neutralizers, Nucleating agent, flow improver, dye, carbon black, flame retardant, asbestos, glass fiber, whisker titanate, talc, silica, calcium carbonate, pumice, silica alumina, kaolin, mica, etc., do not impair the object of the present invention. You may add in the range.

In the present invention, the heat kneading is performed at 100 ° C. to 3 ° C.
It is carried out at 00C, preferably at 160C to 250C. Heat kneading at a high temperature may increase the decomposition odor of the polymer. The heating time is desirably 30 minutes or more. Further, the kneading can be carried out with a Banbury mixer, a twin-screw extruder or other ordinary kneading machines. The obtained silicone-modified styrene-based thermoplastic elastomer can be formed into the above-mentioned various molded products by an injection molding method, an extrusion molding method, a rotational molding method, a compression molding method, or the like.

[0027]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the following examples, “parts” means “parts by weight”.

[Workability] The values of melt index (MI) and flow index (FI) are shown as the degree of workability. These are the values measured at a melt flow rate test method of JIS K 6760 of MI at 190 ° C. and a load of 2.16 kg, FI of 190 ° C. and a load of 2
It is a value measured at 1.6 kg, and the unit is g / 1.
0 minutes. [Blocking Resistance] Two sheets of 10 cm × 10 cm × 1 mm produced from the composition to be tested were stacked, and a load of 4 kg was placed on the sheets at 23 ° C. for 24 hours, and then a blocking tester (manufactured by Sokki Keiso Co., Ltd., TA −
The blocking value was measured at 8 mm / min. The smaller the blocking value (g), the better the blocking resistance.

Example 1 As an organopolysiloxane,
Silicone gum stock having a methylvinylsiloxane content of 0.8 mol% and a plasticity of 80 at 70 ° C. (trade name: RZ76
01, manufactured by Nippon Unicar) 40 parts, styrene-ethylene-butene-1-styrene block copolymer (SEBS) (trade name: Lavalon 5301C, manufactured by Mitsubishi Yuka) as a styrene-based thermoplastic elastomer, 100 parts, 1,13-tetra 1 part of decadiene and 0.07 part of 1,3-di (t-butylperoxyisopropyl) benzene (trade name: Perbutyl P, manufactured by NOF Corporation) are mixed with a Banbury mixer for 180 parts.
Kneaded at 7 ° C for 7 minutes. The kneaded product had reacted uniformly. The MI and FI of this kneaded product were 0.06 and 1 respectively.
00 and the blocking value was 230 g.

Comparative Example 1 A methylvinylsiloxane content of 0.
8 parts by mole, 40 parts of a plastic 80 silicone gum stock (trade name: RZ7601, manufactured by Nippon Unicar) at 70 ° C.,
SEBS (trade name Lavalon 5301C, manufactured by Mitsubishi Yuka) 1
00 parts and 1,3-di (t-butylperoxyisopropyl) benzene (trade name: Perbutyl P, manufactured by NOF Corporation)
0.07 part was kneaded at 180 ° C. for 7 minutes using a Banbury mixer. Unreacted organopolysiloxane remained in the kneaded product. Then, the mixture was further kneaded at 180 ° C. for 5 minutes to obtain a reaction product. M of this final kneaded material
I and FI were 0.07 and 98, respectively, and the blocking value was 260 g.

Example 2 Methylvinylsiloxane content
8 parts by mole, 25 parts of a plastic 80 silicone gum stock (trade name: RZ7601, manufactured by Nippon Unicar) at 70 ° C.
SEBS (trade name Lavalon 5301C, manufactured by Mitsubishi Yuka) 1
00 parts, 1 part of triallyl isocyanurate and 1,3
0.06 parts of -di (t-butylperoxyisopropyl) benzene (trade name: Perbutyl P, manufactured by NOF Corporation) was kneaded at 180 ° C for 7 minutes using a Banbury mixer. The kneaded product had reacted uniformly. MI and FI of this kneaded material
Was 0.45 and 190, respectively, and the blocking value was 360 g.

Example 3 Methylvinylsiloxane content
8 mole%, 10 parts of a plastic 80 silicone gum stock (trade name: RZ7601, manufactured by Nippon Unicar) at 70 ° C.
SEBS (trade name Lavalon 5301C, manufactured by Mitsubishi Yuka) 1
00 parts, 1 part of triallyl isocyanurate and 1,3
0.05 parts of di- (t-butylperoxyisopropyl) benzene (trade name: Perbutyl P, manufactured by NOF Corporation) was kneaded at 180 ° C. for 7 minutes using a Banbury mixer. The kneaded product had reacted uniformly. MI and FI of this kneaded material
Was 0.9 and 250, respectively, and the blocking value was 470 g.

Comparative Example 2 SEBS which is an unmodified styrene-based thermoplastic elastomer (trade name: Lavalon 5301C,
The MI and FI of Mitsubishi Yuka were 0.46 and 273, respectively, and the blocking value was 930 g.

Example 4 Methylvinylsiloxane content
8 parts by mole, 40 parts of a plastic 80 silicone gum stock (trade name: RZ7601, manufactured by Nippon Unicar) at 70 ° C.,
100 parts of styrene-butadiene-styrene copolymer (SBS) (trade name: Kaliflex KX65S, manufactured by Shell Chemical) as a styrene-based thermoplastic elastomer, 1,13
1 part of tetradecadiene and 0.07 part of 1,3-di (t-butylperoxyisopropyl) benzene (trade name: Perbutyl P, manufactured by NOF Corporation) were kneaded at 180 ° C. for 7 minutes using a Banbury mixer. The kneaded product had reacted uniformly. The blocking value of this kneaded product was 280 g.

Comparative Example 3 SBS which is an unmodified styrene-based thermoplastic elastomer (trade name: Kaliflex KX65)
S, manufactured by Shell Chemical Co.) was 720 g.

[0036]

As described in detail above, the silicone-modified styrenic thermoplastic elastomer of the present invention has excellent advantages of the styrenic thermoplastic elastomer itself,
Good processability (no need for mastication step, no vulcanization step, soluble in a wide range of solvents, low viscosity, applicable to the same processing methods as general thermoplastics, compatible with many types of compounds , Compounding, etc.) and excellent physical properties (high strength, high elasticity, low temperature properties, acid resistance, alkali resistance, ozone resistance, oxidation resistance, UV resistance, heat resistance, etc.) This is an improvement in blocking performance. Moreover, according to the resin of the present invention, bleeding or the like does not occur on the surface of a molded product when wax is used for imparting blocking resistance.

Accordingly, the present invention provides a molded article having improved blocking resistance without causing bleeding on the surface,
It has made it possible to provide food supplies, automobile supplies, wire-covered goods, daily necessities, sports goods, leisure goods, health goods, civil engineering construction goods, marine marine goods, aerospace goods, textile and textile goods, sanitary goods, and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C08K 5/00 C08K 5/00 5/14 5/14 C08L 9/06 C08L 9/06 25/00 25/00 53/02 53 / 02 83/04 83/04 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 291/00 C08F 283/12 C08F 257/00 C08F 8/42 C08L 53/02 C08L 25/00 C08L 9 / 06 C08L 83/04 C08K 5/00 C08K 5/14 C08J 5/00

Claims (3)

(57) [Claims] 1. Styrene-based thermoplastic elastomer 100
(A) Formula I: (Wherein, R ¹ represents an aliphatic unsaturated group, R ² represents an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated group, and a
And b are the following conditions: 0 ≦ a <1, 0.5 <b <3, 1
1 to 500 parts by weight of an organopolysiloxane represented by <a + b <3), (B) 0.1 to 10 parts by weight of a polyfunctional monomer, and (C) 0.0 of an organic peroxide.
A method for producing a silicone-modified styrene-based thermoplastic elastomer, comprising heating and kneading a composition obtained by adding 0.5 to 1 part by weight. 2. A silicone-modified styrenic thermoplastic elastomer produced by the method according to claim 1. 3. A molded article produced from the silicone-modified styrenic thermoplastic elastomer according to claim 2.