JPS6254139B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improved thermoplastic polymer compositions, and more particularly, to (a) an ionomer component;
(b) Physical properties of a block copolymer consisting of a vinyl aromatic compound and a conjugated diene compound, and a component of a modified block copolymer in which a molecular unit containing a dicarboxylic acid group or its derivative group is bonded. The present invention relates to improved thermoplastic polymer compositions. Ionomers, represented by DuPont's trade name "Surlyn", are polymers that have several characteristics not found in conventional polyolefin polymers, and are a material that has been attracting attention in recent years. The above-mentioned "Surlyn" is obtained by reacting ethylene-methacrylic acid copolymer with metal ions such as sodium and zinc to create ionic crosslinking, and its characteristics include transparency and appropriate flexibility. It has cold resistance, abrasion resistance, heat sealability, adhesion to metals, melt strength, oil resistance, and chemical resistance, and can be molded and processed in the same way as ordinary polyolefin polymers. Because of this, packaging materials such as films and sheets, coatings, shoe soles,
It is used in various applications such as molded products such as golf balls and toys, and adhesive layers for laminates. However, ionomers such as the above-mentioned "Surlyn" do not have good water resistance, particularly water resistance in terms of adhesive strength, and have the disadvantage that the adhesive surface tends to peel off when exposed to high humidity or when immersed in water. On the other hand, block copolymers consisting of vinyl aromatic compounds and conjugated diene compounds, especially styrene-butadiene block copolymers, are polymeric materials that have attracted attention in recent years. Among such styrene-butadiene block copolymers, the styrene content is relatively low, and the copolymer contains two or more polystyrene blocks and one polybutadiene block.
Those having more than 10% have the properties of thermoplastic elastomers, and have the advantages of the rubber elasticity of vulcanized rubber and the processability of thermoplastic plastics, and are used as molding materials for shoe soles, polystyrene resins, polyolefin resins, Used as a modifier. An example of such a thermoplastic elastomer styrene-butadiene block copolymer is the product name "Tuffprene".
(manufactured by Asahi Kasei Industries), "Rusoprene T" (manufactured by Nippon Elastomers), "Kraton" (manufactured by Ciel Chemical), etc. are known. In addition, the block copolymer with a relatively high styrene content is a transparent impact-resistant resin, and the product name is "K".
Resin” (manufactured by Philips Petroleum),
"Clearen" (manufactured by Denki Kagaku) is well known and is used in fields centered on packaging materials such as sheets, films, and hollow products. A block copolymer composed of a vinyl aromatic compound and a conjugated diene compound, of which the above-mentioned styrene-butadiene block copolymer is a typical example, has good compatibility with styrene resins etc. as described above.
Although it is used as a modifier for these, its compatibility with the ionomer is not necessarily good. Regarding the composition of the ionomer and the above-mentioned block copolymer, the use as a foam is disclosed in JP-A No. 52-47863, but although there is some mutual modification effect by blending, the adhesive property is There are not many improvements. Therefore, the present inventors conducted intensive research to improve the compatibility between the ionomer and the above block copolymer and enhance the mutual modification effect. It was discovered that the above object could be achieved by using a modified block copolymer subjected to an addition reaction, and the present invention was completed. That is, the present invention uses component (a): a copolymer of α,β-unsaturated carboxylic acid and other monomer as a base polymer, and monovalent, divalent and 1 to 50% by weight of an ionomer that is ionically crosslinked with one or more trivalent metal ions; component (b): a vinyl aromatic compound content of 5 to 95%;
A modified block copolymer in which 1 to 50 molecular units containing a dicarboxylic acid group or its derivative group are bonded per molecule of the block copolymer to a block copolymer consisting of a vinyl aromatic compound and a conjugated diene compound in the same amount by weight. 50 to 99% by weight of an ionomer-containing thermoplastic polymer composition. The present invention will be explained in more detail below. The ionomer, which is component (a) of the present invention, uses a copolymer of α,β-unsaturated carboxylic acid as a monomer containing a carboxyl group and other copolymerizable monomers as a base polymer. It is a polymer that is ionically crosslinked by one or more of monovalent, divalent, and trivalent metal ions contained in the polymer. The above-mentioned base polymers include nonpolar monomers such as olefins such as ethylene, propylene, and butene, and styrene, and α,β-unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and α,β-unsaturated monocarboxylic acids such as maleic acid. - Copolymers with unsaturated dicarboxylic acids are usually used, especially olefins in an amount of 50 mol% or more and α,β-unsaturated carboxylic acids in an amount of 0.2 to 25 mol%.
The olefin-α,β-unsaturated carboxylic acid copolymer is preferred. Ionomers are produced by reacting a mono- to trivalent metal compound with the above-mentioned base polymer, such as a copolymer of olefin-α,β-unsaturated carboxylic acid, as shown in Japanese Patent Publication No. 39-6810. It can be obtained by letting These metal compounds neutralize 10 to 100 mol% of the carboxylic acid groups in the copolymer,
Added to participate in ionic crosslinking. Examples of olefin-α,β-unsaturated carboxylic acid copolymers include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-itaconic acid copolymer, ethylene-maleic acid copolymer, Examples include ethylene-acrylic acid-methacrylic acid copolymer, ethylene-propylene-methacrylic acid copolymer, etc. Ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer containing an unsaturated monocarboxylic acid as a component preferable. Furthermore, the metal ions used in the production of the above ionomer are monovalent to trivalent ions of metals in groups , , -A and groups of the periodic table; examples thereof include Na ⁺ , Li ⁺ , K ⁺ , 1 such as Cs ⁺ and Ag ⁺
Valence ions, Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Zn ²⁺ , Sr ²⁺ ,
Examples include divalent ions such as Hg ²⁺ and Fe ²⁺ , and trivalent ions such as Al ³⁺ and Fe ³⁺ . These are reacted with the base polymer as compounds such as hydroxides, alcoholates, and lower carboxylic acid groups. Further, the above ionomer is olefin-α,
β-unsaturated carboxylic acid ester copolymers, such as ethylene-methyl methacrylate copolymers and ethylene-methyl acrylate copolymers, are saponified with mono- to trivalent metal hydroxides, and It can also be produced by a method of partially neutralizing a compound to partially convert it into a carboxylic acid.
Can be used as an ingredient. In addition to the above-mentioned product name "Surlyn", commercially available ionomers that can be used in the present invention include:
Examples include the product name "Corpolen" (manufactured by Asahi Dow). A mixture of two or more ionomers can also be used in the composition of the present invention. Next, in the present invention, the block copolymer of component (b) is obtained by adding dicarboxylic acid to a block copolymer (hereinafter referred to as "block copolymer") consisting of a vinyl aromatic compound and a conjugated diene compound as a base. The group or its derivative group is preferably a polymer to which molecular units containing a dicarboxylic acid anhydride group are bonded. The block copolymer serving as the base has a vinyl aromatic compound content of 5 to 95% by weight, preferably
15-85% by weight. It contains one or more, preferably two or more, polymer blocks A mainly composed of a vinyl aromatic compound, and one or more polymer blocks B mainly composed of a conjugated diene compound, and the weight of each polymer block is The ratio is preferably A/B.
It ranges from 10/90 to 90/10. In the above range, if the content of vinyl aromatic compounds is 70% by weight or less, more specifically 50% by weight or less, a rubbery block copolymer is obtained, and the content of vinyl aromatic compounds is 70% by weight or less. If it exceeds the amount, a resinous block copolymer is formed. This state is maintained even after modification with dicarboxylic acid groups or derivatives thereof.
Furthermore, the specific properties of the composition of the present invention, such as hardness, vary depending on the vinyl aromatic compound content of the block copolymer. In block A of the block copolymer, the content of vinyl aromatic compounds is 60% by weight or more, preferably 80% by weight or more, particularly preferably 100% by weight, while in block B, the content of vinyl aromatic compounds is The content is less than 40% by weight, preferably 30
% by weight or less. If minor components are present in each block, the distribution may be random, tapered, partially block-like, or a combination thereof. If each polymer block is two or more,
They can have the same structure or different structures. Examples of the vinyl aromatic compound constituting the block copolymer include styrene, α-methylstyrene, vinyltoluene, etc., and examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, etc. As the block copolymer of the present invention, a styrene-butadiene block copolymer is preferred. The number average molecular weight of block A or B is 1000~
300000, preferably in the range of 5000-100000,
The number average molecular weight of the entire block copolymer is 10,000~
500000, preferably 20000-300000, and the molecular weight distribution is 1.01-10. Further, the molecular structure of the block copolymer may be linear, branched, radial obtained by using a polyfunctional coupling agent, or any combination thereof. The conditions for the polymer structure of the block copolymer described above are desired in order for the modified block copolymer to achieve the effects of the present invention. Further, it is possible to combine two or more types of block copolymers having different structures. The block copolymer having the above structure is usually produced by combining a vinyl aromatic compound and a conjugated diene compound as monomers in an inert hydrocarbon solvent such as benzene, toluene, hexane, or cyclohexane using an organic lithium compound such as butyllithium as a catalyst. It is obtained by anionic living polymerization method. Furthermore, by reacting the block copolymer having a lithium active end obtained by the above method with a multifunctional coupling agent such as carbon tetrachloride, silicon tetrachloride, etc., a branched or radial block copolymer can be produced. It is also possible to do this. In the present invention, any polymer obtained by any polymerization method can be used as long as it falls within the above range. Next, the modified block copolymer of the present invention is obtained by subjecting the above block copolymer to an addition reaction with an unsaturated dicarboxylic acid or its derivative, and the unsaturated dicarboxylic acid or its derivative is added to the active unsaturated bond position. It is added to the conjugated diene moiety of the block copolymer. In order for the composition of the present invention to have the desired properties, it is preferable to add 1 to 50, preferably 1 to 20 unsaturated dicarboxylic acids or derivatives thereof per molecule of the block copolymer. The number of additions above is 1
Even a small amount of ~2 produces a significant improvement effect. Even if the number of additions exceeds 50, the effect will be less than that. The amount of bonding of molecular units containing dicarboxylic acid groups or derivative groups thereof in the modified block copolymer is
The dicarboxylic acid group or its derivative group in the modified block copolymer obtained by the method described below can be easily determined by measuring it with an infrared spectrophotometer, titration, or the like. Examples of unsaturated dicarboxylic acids or derivatives thereof include maleic acid, maleic anhydride, fumaric acid,
Itaconic acid, cis-4-cyclohexene-1,2
-dicarboxylic acids and their anhydrides, endo-cis-bicyclo[2,2,1]-5-heptene-2,
There are 3-dicarboxylic acids and acid anhydrides, esters, amides, imides, etc. of these dicarboxylic acids.
Maleic acid, fumaric acid and maleic anhydride are preferred. The modified block copolymer can be obtained, for example, by reacting a block copolymer with an unsaturated dicarboxylic acid or a derivative thereof in a molten state or a solution state, with or without the use of a radical initiator. The method of producing these block copolymers is not particularly limited in the present invention, but the modified block copolymers obtained may contain undesirable components such as gels, or may have low fluidity and poor processability. A manufacturing method that results in poor performance is not preferred. One preferred method is to carry out the addition reaction in an extruder or the like in the presence of a radical inhibitor under melt mixing conditions that do not substantially generate radicals, as shown in Japanese Patent Application No. 53-99102. Can be mentioned. In the composition of the present invention, by mixing the components (a) and (b), the metal ions in the component (a) can be mixed with the dicarboxylic acid group of the modified block copolymer of the component (b) or its dicarboxylic acid group. Since components (a) and (b) are co-ionically crosslinked by metal ions by reacting with the derivative group, the compatibility of both components is greatly improved. The co-ionic crosslinking described above can be confirmed using, for example, an infrared spectrophotometer. Further, in the present invention, as the modified block copolymer of component (b), it is also possible to use an ionic crosslinked product which has been ionically crosslinked in advance with mono- to trivalent metal ions. When a modified block copolymer that has been ionically crosslinked in advance is used, the composition is further improved in hardness, tensile stress, etc., and a tough material is obtained. In the composition of the present invention, component (a) is 1% to 50% by weight, and component (b) is 50% to 99% by weight. If the content of component (a) is less than 1% by weight, there is no effect of improving oil resistance, and if it exceeds 50% by weight, elongation decreases, which is not preferable. The composition of the present invention is characterized by the heat sealability and abrasion resistance of the modified block copolymer when it contains the modified block copolymer of component (b) in an amount of 50% by weight or more, preferably 60 to 99% by weight. , oil resistance, especially oil resistance, is improved. Furthermore, the composition of the present invention has good adhesion to various materials such as metals, various thermoplastic polymers, and paper, and can be used in one or two layers of a laminate of these materials and two layers.
It is useful as an adhesive layer for a laminate of more than one type of material, and can particularly exhibit its water resistance. Furthermore, the composition of the present invention is not only a useful material in itself, but can also be made into other useful materials by forming a composition with various thermoplastic polymers. The composition of the present invention can be prepared using a conventional apparatus for mixing polymeric substances depending on the composition ratio of each component. Examples of the mixing device include an extruder, a mixing roll, a Banbury mixer, a kneader, etc. In the present invention, a melt mixing method using an extruder is particularly preferred. In addition, the thermoplastic polymer composition of the present invention may contain reinforcing agents or fillers such as calcium carbonate, silica, carbon black, glass fiber, clay, process oil, polyethylene glycol, etc., to the extent that its properties are not impaired. It is also possible to add plasticizers such as phthalate esters. Further, other additives such as heat stabilizers, antioxidants, ultraviolet absorbers, colorants, pigments, etc. may be added, and a foaming agent may be further added to the composition of the present invention to form a foam. is also possible. The thermoplastic polymer composition of the present invention can be molded by various conventional molding methods, such as extrusion molding, injection molding, and calendar molding, and can be molded into various molded products, such as mechanical parts, automobile parts, electrical appliance parts, etc. Various fields such as toys, industrial parts, belts, hoses, footwear, medical supplies, anti-vibration rubber, daily necessities, miscellaneous goods, building materials, sheets, films, blow molded products, and solution-type and hot-melt-type adhesives and adhesives. It is a useful composition that can be used for. Hereinafter, some Examples will be shown, but these are intended to explain the present invention more specifically, and are not intended to limit the scope of the present invention. In addition, reference examples are also shown. Reference Example [Preparation of Modified Block Copolymer] A modified block copolymer (Sample P) in which maleic anhydride was grafted by the method shown below using Sample P, which is a thermoplastic elastomer of styrene-butadiene block copolymer. I got it. Note that sample p was obtained in a hexane solution using n-butyllithium as a polymerization catalyst, and is considered to have the following structure based on the polymerization method and analysis results. Polymer structure: B ₁ −S ₁ −B ₂ −S ₂ (linear) B ₁ = 18% by weight [B] / [S] = 16/2
(Tapered) S ₁ = 17% by weight [B] / [S] = 0/17 B ₂ = 49% by weight [B] / [S] = 46/3
(Tapered) S ₂ = 16% by weight [B] / [S] = 0/16 However, B _o ... Polymer block mainly composed of butadiene S _o ... Polymer block mainly composed of styrene The integer n is the molecular chain. Represents the order along. [B]... Butadiene content (weight % based on the entire block copolymer) [S]... Styrene content (weight % based on the entire block copolymer) (Same description will be given in the following examples.) Styrene content Amount: 38% by weight Block styrene content: 33% by weight Weight average molecular weight (Mw): 81000 Number average molecular weight (Mn): 62000 Melt index: 11.0g/10min (JIS-K-6870, load 5Kg, 200℃ ) 1.5 parts by weight of maleic anhydride and 0.3 parts by weight of BHT as an anti-gelling agent for 100 parts by weight of sample p.
(butyl hydroxytoluene) and 0.2 parts by weight of phenothiazine were added, and these were mixed uniformly using a mixer. This mixture was supplied to a 40 mm extruder (single screw, full-flight screw, L/D=24) under a nitrogen atmosphere, and a modification reaction was carried out at a cylinder temperature of 190 to 210°C. The obtained polymer was dried under reduced pressure to remove unreacted maleic anhydride. The analysis results of the modified block copolymer (sample P) are as follows:
The index was 7.3 g/10 min, the toluene insoluble content was 0.05% by weight, and the amount of maleic anhydride added was 0.70 parts by weight per 100 parts by weight of the block copolymer, as determined by titration with sodium methylate. From this measured value, the amount of maleic anhydride bonded in Sample P is approximately
There were 4.4 pieces. In addition, sample q (styrene-butadiene block copolymer with a structure of styrene/butadiene/styrene = 37/26/37, melt index 8.4 g/
10min), sample r (commercially available styrene-butadiene block copolymer Asaprene T-431, styrene content 30% by weight, melt index 10.3g/
Sample Q and Sample R of modified block copolymers were added by adding maleic anhydride using the same extruder as that used to obtain Sample P.
I got it. Table 1 shows these melt indexes and the amount of maleic anhydride added. From Table 1, the average amount of maleic anhydride bonded in Samples Q and R was about 6 and about 3, respectively, per molecule of the block copolymer.

[Table] Examples 1 to 3, Comparative Examples 1 to 3 Surlyn A-1706 as the ionomer for component (a)
Using sample P and sample R as modified block copolymers of component (b), the composition shown in Table 2 was heated at 180°C.
(Examples 1 to 3). For comparison, compositions of Comparative Examples 1 to 3 were obtained in the same manner using samples p and r of unmodified block copolymers. Table 2 shows the physical property values of compression molded products of these compositions and samples obtained in Reference Examples. It can be seen that the tensile stress of each of the compositions using the modified block copolymers of Examples was improved, and furthermore, the oil resistance of the block copolymers was greatly improved by adding a small amount of ionomer. In addition, analysis using an infrared spectrophotometer confirmed that the acid anhydride groups in the modified block copolymer were involved in ionic crosslinking.

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Claims (1)

[Claims] 1 (a) Component: A copolymer of α,β-unsaturated carboxylic acid and other monomers is used as a base polymer, and monovalent and divalent and 1 to 50% by weight of an ionomer that is ionically crosslinked with one or more trivalent metal ions, component (b): content of vinyl aromatic compound is 5 to 95% by weight
A modified block copolymer in which 1 to 50 molecular units containing a dicarboxylic acid group or its derivative group are bonded per molecule of the block copolymer to a block copolymer consisting of a vinyl aromatic compound and a conjugated diene compound. 99% by weight of an ionomer-containing thermoplastic polymer composition. 2 Claim 1 in which the base polymer is an olefin-α,β-unsaturated monocarboxylic acid copolymer
Compositions as described in Section. 3. The composition according to claim 2, wherein the olefin-α,β-unsaturated monocarboxylic acid copolymer is an ethylene-acrylic acid copolymer or an ethylene-methacrylic acid copolymer. 4 α, β as monomer units in the base polymer
- The composition according to claim 1, wherein the content of unsaturated carboxylic acid is 0.2 to 25 mol%. 5. The composition according to any one of claims 1 to 4, wherein the dicarboxylic acid group or its derivative group is a dicarboxylic acid anhydride group. 6. Claim 1, wherein the content of the vinyl aromatic compound in the block copolymer consisting of a vinyl aromatic compound and a conjugated diene compound is 5 to 70% by weight.
The composition according to any one of Items 1 to 5. 7. Any one of claims 1 to 5, wherein the content of the vinyl aromatic compound in the block copolymer consisting of a vinyl aromatic compound and a conjugated diene compound is more than 70% by weight and not more than 95% by weight. The composition described in. 8. The composition according to claim 1, wherein component (a) and component (b) are coionically crosslinked by metal ions in component (a).