JPS6129264B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic resin laminate with excellent adhesive strength retention at high temperatures, and more specifically, to a thermoplastic resin laminate having an adhesive layer made of a block copolymer-modified thermoplastic resin. Regarding laminates. Adhesive strength retention at high temperatures is important, for example, when laminates are used as food packaging materials and are used for retort sterilization, especially
These properties are required during high-temperature retort sterilization at temperatures of 130°C or higher, and are also required for bonding parts of hot water pipes. Conventionally, adhesives that maintain good adhesive strength even at such high temperatures have mostly been curable types such as urethane adhesives and epoxy adhesives, which have been unsatisfactory in terms of workability. On the other hand, styrene is a thermoplastic resin type.
Adhesive strength is extremely low at temperatures above 100°C, such as butadiene block copolymer and ethylene-vinyl acetate copolymer, and excellent high-temperature adhesion is achieved only with certain resins, such as polycarbonate versus polyester. There are things that exist, but
No thermoplastic adhesive with excellent high-temperature adhesion properties has been found for various thermoplastic resins. The present invention has discovered that by using a block copolymer-modified thermoplastic resin as described in detail below as such a thermoplastic adhesive, it has high-temperature adhesion to a fairly wide range of thermoplastic resins. The gist of the present invention is to provide a multilayer laminate of thermoplastic resins in which at least one interface is an adhesive layer made of a block copolymer thermoplastic resin.
A block copolymer thermoplastic resin is represented by the general formula (AB) _n A or (AB) _o X consisting of a conjugated diene and an aromatic vinyl (where A is an aromatic vinyl polymer block, B is substantially a conjugated diene polymer block, m is 1 or 2, n is an integer from 2 to 8, and X is a polyfunctionality in which n (A-B) type polymer chains are bonded at the terminal of B. a linear or branched block copolymer having an aromatic vinyl content of 10 to 70% by weight, or a mixture thereof with a maleic anhydride compound, or a modified product thereof. The final modified product obtained by adding 0 to 10 parts by weight of a monovalent or divalent metal oxide, hydroxide, organic acid salt, or alkoxide to 100 parts by weight contains 0.1 to 10 parts by weight of maleic anhydride residues. The thermoplastic resin layer other than the modified block copolymer is polyvinylidene chloride resin, polyvinyl chloride resin, polyolefin resin, polyamide resin, polyester resin. It is a thermoplastic resin laminate characterized by comprising one or more resin layers selected from the group of polycarbonate resins and polycarbonate resins. The present invention will be explained in detail below. The block copolymer-based thermoplastic resin for adhering at least one interface of the multilayer laminate is a non-modified block copolymer modified as described below. The unmodified block copolymer is a linear block copolymer (A-B) - _n A or a branched block copolymer (A-B) _o X, and examples of the conjugated diene constituting these include butadiene, Isoprene, 2,
3-dimethylbutadiene, etc. are used, and aromatic vinyls include, for example, styrene, vinyltoluene,
Tertiary butyl styrene, vinylnaphthalene, etc. are used. Among them, a preferred AB combination is butadiene and styrene or isoprene and styrene. In addition, as a polyfunctional binder that binds X constituting (A-B) _o X, that is, n (A-B) type polymer chains, for example,

[Formula] (CH ₃ ) ₂ Dehalogenated residue of bifunctional binder such as SiCl ₂ , Sncl ₄ ,

Dehalogenated residues of polyfunctional binders such as [Formula] are used. Further, in the block copolymer (AB) _o X, n is preferably in the range of 2 to 8. This is because if n is 9 or more, manufacturing becomes difficult. The aromatic vinyl content in the block copolymer is
It should range from 10 to 70% by weight, preferably from 12 to 50% by weight. This is because if the amount is less than the above range, the cohesive force will be weak and cohesive failure will occur easily, and if it is more than the above range, the adhesive force will be reduced. The modified block copolymer must be obtained by reacting the above unmodified block copolymer with a maleic anhydride compound. The maleic anhydride compound referred to in the present invention has the general formula

It is a compound represented by the formula: Here, R is an alkyl group or an aryl group, and for example, H, CH ₃ phenyl, etc. are preferably used, and one or a mixture of two or more of these is used.
Therefore, the maleation reaction referred to in the present invention does not simply refer to a reaction with maleic anhydride, but refers to a reaction with any of these compounds. This reaction is carried out using a known maleation reaction method, such as a method using light irradiation, a method using a radical generator, a method using only heat, or a combination of these methods, and the molten state of the block copolymer is , in a dispersed state or in a dissolved state. The amount of the reacted maleic anhydride compound is 0.1 to 10% by weight of the maleic anhydride residue bonded in the final modified product mixed with the metal compound described below if necessary.
That is. In order to satisfy high temperature adhesion and moldability, it is preferably 0.2 to 8% by weight, and the melt viscosity of the final modified product is 4.0× at 175°C.
1.0× ¹⁰³ to 1.0× under shear stress of ¹⁰⁶ dyn/ ^cm2
10 ⁶ poise, and more preferably within the range shown in the shaded area in FIG. Incidentally, the maleic anhydride residue content referred to in the present invention is the value at the stage where the maleic anhydride residue bonded to the polymer has an anhydride structure. The quantitative method uses a block copolymer mixed with a predetermined amount of styrene-maleic anhydride alternating copolymer in the infrared absorption spectrum.
A calibration curve was obtained by calculating the absorbance ratio between the C=O absorption (1780 cm ^-1 ) of maleic anhydride residue and the characteristic absorption of the aromatic vinyl moiety of the block copolymer. Since this maleated block copolymer already has excellent adhesion to various thermoplastic resins at high temperatures, this maleated product can be used as is as an adhesive, but the The anhydride structure is modified, for example, by hot water treatment or alkali treatment followed by acid treatment to create a dicarboxylic acid-open structure, or anhydride or dicarboxylic acid-open structure is treated with methanol, Half esters made by reacting alcohols such as ethanol are also used. In addition, monovalent or divalent metal oxides, hydroxides, organic acid salts,
10 at least one selected from alkoxides
It may be added in an amount of not more than 5 parts by weight, preferably not more than 5 parts by weight, and more preferably 0.001 to 3 parts by weight. This is because ionic bonds are introduced, which further improves the adhesive properties at high temperatures. A known method can be used for this ionic bond introduction reaction. Furthermore, it is also possible to use an anhydride which is opened into a carboxylic acid group or made into a half ester prior to this ionic bond introduction reaction. Examples of metal compounds used include organic hydrochloric acids such as sodium hydroxide, magnesium acetate, zinc formate, and magnesium formate, oxides such as zinc oxide, and alkoxides such as sodium methoxide and sodium ethoxide. The reason why the amount of the metal compound to be added is limited to the above range is that if it exceeds this amount, the melt viscosity of the product becomes too high, leading to a decrease in adhesive properties. It goes without saying that additives such as antioxidants and stabilizers can be added to the modified block copolymer as necessary. On the other hand, examples of the thermoplastic resin layer that can be bonded at high temperatures using the modified block copolymer include polyvinylidene chloride resins, polyvinyl chloride resins, polyolefin resins, polyamide resins, polyester resins, and polycarbonate resins. A layer of one or more selected resins may be used. The polyvinylidene chloride resin referred to in the present invention is a copolymer containing vinylidene chloride as a main component, to which various additives including a plasticizer are added as necessary. Examples of polyvinyl chloride resins include vinyl chloride homopolymers, copolymers containing vinyl chloride as a main component, modified products of these such as post-chlorinated products, or mixtures containing these as main components. Furthermore, polyolefin resins are typically polyethylene resins and polypropylene resins, among which polyethylene resins include polyethylene, copolymers mainly composed of ethylene,
Metal ion crosslinked products of ethylene copolymers, oxides of ethylene-vinyl acetate copolymers, etc. are preferably used, and as polypropylene resins, polypropylene, copolymers containing propylene as a main component, etc. are preferably used. In addition, polyamide resins include 6.6 nylon, 6 nylon, 12 nylon,
Preferred examples include nylon 6/66 copolymer, polyethylene terephthalate, polycyclohexylene 1,4-dimethylene terephthalate, and the like as the polyester resin, and bisnol A polycarbonate as the polycarbonate. The thermoplastic resin and the modified block copolymer can be laminated by conventional melt molding methods such as coextrusion such as heat compression molding, in-die lamination, and outside-die lamination. At this time, it is not necessary that all the thermoplastic resin be melted in any molding, and it is also possible that only the adhesive layer is melted. Examples are shown below. Note that all "parts" and "%" in the following examples are expressed by weight. Example 1 Styrene-butadiene-styrene block copolymer (hereinafter abbreviated as SBS) synthesized in benzene solvent using n-butyllithium as a catalyst [butadiene/styrene = 67.5/32.5 (weight ratio), 25°C
ηsp/C=0.75d/g at 4g/in toluene
60 g and 1.5 kg of toluene were placed in a 5-separable flask and dissolved while heating to 90° C. under a nitrogen atmosphere. After adding 4.5 g of maleic anhydride to this, 0.3 g of benzoyl peroxide was added,
The reaction was allowed to proceed for 4 hours. Furthermore, dimethylformamide in which 0.3 g of zinc acetate (dihydrate) was dissolved was added to this reaction system.
400ml was added and stirred at 80°C for 3 hours. The obtained solution was poured into methanol to precipitate it, and after washing with methanol at room temperature, a small amount of a phenolic antioxidant was added, and then vacuum-dried at 45°C. The maleic anhydride residue in the obtained modified SBS was 2.4%. Furthermore, the melt viscosity of untreated SBB and modified SBS measured by a melt tension tester using a nozzle with an inner diameter of 1 mm and a length of 3 mm was 175°C and a shear stress of 4 × 10 ⁶ dyn/.
They were 3×10 ³ poise and 8×10 ⁴ poise under cm ² , respectively. Laminates of various polymer sheets as shown in Table 1 were prepared using modified SBS and untreated SBS as a control layer for the contact layer. Lamination was performed by hot press molding by sandwiching a modified or unmodified SBS sheet between polymer sheets of the same or different types. This hot press molding condition is that when vinylidene chloride-vinyl chloride copolymer is used as the base material, it is preheated at 170℃ for 1 minute and pressurized at 50Kg/cm ² for 0.5 minutes; otherwise, it is preheated at 200℃ for 1 minute. and 50 for 0.5 minutes
Kg/ ^cm2 pressurized. The polypropylene is "Sumitomo Noblen W-111" manufactured by Sumitomo Chemical, and the vinylidene chloride-vinyl chloride copolymer is vinylidene chloride/
A copolymer with a vinyl chloride weight ratio of 80/20 containing 3% plasticizer, polycarbonate made by Teijin "Teijin Panlight", nylon made by Unitika "Unitika Nylon 6", ethylene-vinyl acetate The saponified copolymer was "EVAL" manufactured by Kuraray, and the polyvinyl chloride was "S-901" manufactured by Kureha Chemical Co., Ltd., to which 2 parts of an organic tin stabilizer was added. A T-peel test was conducted using a laminate made of the above resin shown in Table 1 as a short fence of 1 cm width at various temperatures at a peel rate of 200 mm/min. The results are shown in Table 1.

【table】

[Table] Example 2 Styrene with a butadiene/styrene weight ratio of 68/32 synthesized using benzene as a solvent and n-butyllithium as a catalyst, and an ηsp/c of 0.72 d/g in a toluene solution with a concentration of 4 g/g. 60 g of -butadiene-styrene block copolymer and 1.5 kg of toluene were placed in two separable flasks and dissolved under a nitrogen atmosphere while heating to 90°C. After adding 3 g of maleic anhydride to this, 0.3 g of benzoyl peroxide was added and reacted for 4 hours. Half of the reaction product solution was taken out and treated in the same manner as in Example 1 to obtain maleated SBS. To the remaining solution was added 200 ml of dimethylformamide in which 150 mg of zinc acetate (dihydrate) was dissolved, and the mixture was stirred at 80°C for 3 hours to obtain maleated and ionically crosslinked SBS. Untreated
The melt viscosities of SBS, maleated SBS, and ionically crosslinked SBS after maleation at 175°C under a shear stress of 4×10 ⁶ dyn/cm ² are 2.5×10 ³ poise and 2.2×, respectively.
10 ⁴ poise, 2.9×10 ⁴ poise. Also, maleation
The amount of maleic anhydride residue in SBS was 1.9%. Using these, laminates as shown in Table 2 were prepared in the same manner as in Comparative Example 1 and Example 1, and the peel strength was measured in the same manner. Table 2 shows the results. As the polyethylene terephthalate in Table 2, Toray's "Lumirror" sheet was used, and the rest was the same as in Example 1.

[Table] Example 3 60 g of "Califlex TR-1102" (styrene-butadiene-styrene block copolymer with a butadiene/styrene weight ratio of 72/28 manufactured by Ciel Chemical Co., Ltd.) and 1.5 kg of toluene were placed in 5 separable flasks. Put it in a nitrogen atmosphere and dissolve it while raising the temperature 90
℃. After adding 3 g of maleic anhydride to this, 0.3 g of benzoyl peroxide was added and reacted for 4 hours. Post-processed and maleated SBS as in other examples
I got it. The amount of maleic anhydride residue in this maleated SBS was 1.6%, and the melt viscosity under the same conditions as in Example 1 was 4.5×10 ⁴ poise. Still unprocessed SBS
was 1×10 ⁴ poise. Using these as an adhesive layer, a laminate of vinylidene chloride-vinyl chloride copolymer and polypropylene was created. The lamination method was to first laminate polypropylene at 200°C, then laminate vinylidene chloride-vinyl chloride copolymer at 170°C, preheating for 1 minute and pressurizing at 50 kg/cm ² for 0.5 minutes. The peel strengths of these are shown in the table below.

[Table] Example 4 In a Pyrex reaction vessel under a nitrogen atmosphere, 26 g of the same SBS used in Example 3 was mixed with 480 g of methyl isobutyl ketone, 100 g of acetone, and 30 g of toluene.
g at 42℃, and 1.3 g of maleic anhydride is dissolved in this at 42℃.
After adding the quartz double tube to the solution, a mercury lamp (Toshiba physical and chemical mercury lamp SHL100UV) was inserted and irradiated with stirring for 2 hours, followed by post-treatment in the same manner as in Example 1 to determine the amount of maleic anhydride residue. A maleated SBS with a concentration of 1.1% was obtained. The melt viscosity under the same conditions as in Example 1 was 7.5×10 ⁴ poise. Using this as an adhesive layer, a polypropylene laminate was produced in the same manner as in the other Examples. The peel strength of this laminate is shown in the table below.

[Table] Example 5 30g of "Solprene 418" (registered trademark name of a styrene-isoprene radial block copolymer with an isoprene/styrene weight ratio of 85/15 manufactured by Philips Chemical) was placed in 750g of toluene and nitrogen was added. The mixture was heated to 90°C and dissolved in an atmosphere. After adding 1.5 g of maleic anhydride to this, 0.15 g of benzoyl peroxide was added and reacted at 90° C. for 4 hours. Half of the reaction product solution was taken out and treated in the same manner as in Example 1 to obtain a maleated block copolymer containing 1.8% of maleic anhydride residues, and the remaining solution was dimethylated with 75 mg of zinc acetate (dihydrate) dissolved therein. Formamide
100 ml was added and stirred at 80°C for 3 hours to obtain a block copolymer into which ionic crosslinking was introduced after maleation. The melt viscosity of the untreated block copolymer, the maleated block copolymer, and the ionically crosslinked block copolymer after maleation at 175°C under a shear stress of 4 × 10 ⁶ dyn/cm ² is 4 × 10 ^{3 .} poise，3.3×
10 ³ poise, 3.7×10 ³ poise. A laminate of polypropylene and nylon was prepared in the same manner as in Example 1 using these block copolymers as adhesive layers. Table 3 shows the results of peel strength measurements.

[Table] As is clear from the above examples, the characteristics of the present invention are not only high adhesive strength at room temperature, but also
At high temperatures such as 130-140°C, it has excellent adhesive strength against many thermoplastic resins. Furthermore, since the laminate of the present invention has excellent water resistance and oil resistance, it is preferably used as a packaging material for high-retort sterilization and as a transport pipe for hot water, high-temperature liquids, and gases. Moreover, since the modified block copolymer that is the adhesive layer is thermoplastic, it can be coextruded with other thermoplastic resins, laminated by hot press molding, etc., and can be used as a multilayer molded product that requires adhesive strength retention at high temperatures. It is much easier to process and mold than conventional products. Furthermore, laminates of various shapes such as films, sheets, bottles, pipes, etc. can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing particularly excellent ranges of high temperature adhesion and processability.

Claims (1)

[Scope of Claims] 1. In a multilayer laminate of thermoplastic resins in which at least one interface is an adhesive layer made of a block copolymer thermoplastic resin, (1) the block copolymer thermoplastic resin contains a conjugated diene and an aromatic General formula consisting of group vinyl (A-B
) - _n A or (A-B) _o represented by X (where A
is an aromatic vinyl polymer block, B is substantially a conjugated diene polymer block, m is 1 or 2, n
is an integer from 2 to 8;
Monovalent or divalent metal oxide per 100 parts by weight of a product obtained by reacting 70% by weight of a linear or branched block copolymer or a mixture thereof with a maleic anhydride compound or a modified product thereof; hydroxide,
Consisting of a modified block copolymer containing 0.1 to 10% by weight of maleic anhydride residues in the final modified product obtained by adding 0 to 10 parts by weight of an organic acid salt or alkoxide and reacting. (2) The block The thermoplastic resin layer other than the modified copolymer is one or more selected from the group of polyvinylidene chloride resin, polyvinyl chloride resin, polyolefin resin, polyamide resin, polyester resin, and polycarbonate resin. A thermoplastic resin laminate characterized by consisting of a resin layer.