JPS6241987B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvements in the extrusion moldability and thermoformability of linear isoprene-styrene block copolymer rubbers having excellent transparency and hot melt adhesive properties. Conventionally, linear isoprene-styrene block copolymer rubber has excellent transparency and has been used as a hot melt adhesive for various synthetic resins such as polyolefins, polyamides, and polymers of monovinyl aromatic compounds, but it has poor extrusion moldability. Another disadvantage was that the thermoformability was poor. Therefore, if this is used as an adhesive layer for a laminated structure formed by coextrusion molding, the extrusion amount will fluctuate during molding, making molding difficult, and the resulting laminated structure is likely to have uneven thickness or deformation during thermoforming. There was a problem. In order to solve this problem, attempts have been made to blend polystyrene or the like, but this may reduce transparency and cause problems in use. The inventors of the present invention have conducted extensive research to solve this problem, and have found that by blending a radial isoprene-butadiene block copolymer with a linear isoprene-styrene block copolymer rubber, extrusion moldability and thermoformability can be improved. Improved properties and linear isoprene
It was discovered that the transparency and hot melt adhesiveness of styrene block copolymer rubber were not impaired, and the present invention was completed. That is, the present invention provides a linear isoprene-styrene block copolymer rubber containing 5 to 40% by weight of a styrene component.
Radial styrene-butadiene block copolymer 50 containing 90% by weight and 50-85% by weight of styrene component
This is an adhesive composition containing ~10% by weight. In view of its structure, the linear isoprene-styrene block copolymer rubber used in the present invention is preferably one in which styrene polymer blocks are arranged at both ends of an isoprene polymer block. Further, it is preferable that the styrene component is contained in an amount of 5 to 40% by weight. If the content of the styrene component is less than 5% by weight or more than 40% by weight, hot melt adhesiveness tends to decrease. The radial styrene-butadiene block copolymer in the present invention has the general formula:
A copolymer represented by (S-B)nX is preferred.
Here, S is a styrene polymer segment, B is a butadiene polymer segment, X is a residue of a binder having n functional groups, n is an integer of 3 or more, and n (S- B) Each branch is attached to the binder X on the B side of the butadiene polymer segment. This radial styrene-isoprene block copolymer is produced by sequential living polymerization of styrene and butadiene using an organolithium initiator such as n-butyllithium, as described in U.S. Pat. No. 3,281,383, and then a butadiene polymer. It can be produced by reacting the active end of the segment with a binder having three or more functional groups. As a binder, epoxidized linseed oil having three or more epoxy groups in the molecule, epoxidized liquid polybutadiene, polyepoxide such as 1,2,5,6,9,10-triepoxydecane, tri(1-aziridinyl), etc. ) polyaziridinyl compounds such as phosphine oxide, benzene-1,2,
Polyisocyanates such as 4-triisocyanate, polyaldehydes such as 1,4,7-naphthalene tricarboxaldehyde, polyhalides such as silicon tetrachloride, polyketones such as 1,4,9,10-anthracentetraone, etc. are suitable. . As the radial styrene-butadiene block copolymer of the present invention, a copolymer containing 50 to 85% by weight, particularly 60 to 80% by weight of a styrene component is suitable from the viewpoints of transparency, extrusion moldability, and thermoformability. . If the styrene component content is less than 50% by weight, transparency, extrusion moldability, and thermoformability will decrease, and if the styrene component content exceeds 85% by weight, the hot melt adhesiveness will tend to decrease. be. Furthermore, in the adhesive composition of the present invention, the blending ratio of the radial styrene-butadiene block copolymer is 10 to 50% by weight in terms of hot melt adhesion, impact resistance, extrusion moldability, and thermoformability. preferred. If the blending ratio of the radial styrene-butadiene block copolymer is less than 10% by weight, extrusion moldability and thermoformability will be poor;
If it exceeds 50% by weight, hot melt adhesiveness tends to decrease. The adhesive composition of the present invention has excellent hot melt adhesion, transparency, extrusion moldability, and thermoformability, as well as excellent impact resistance and moderate rigidity, so it is suitable for adhesion between various synthetic resin layers. suitable.
The adhesive composition of the present invention is suitable for adhering polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamides such as nylon 6, and monovinyl aromatic compound polymers such as polystyrene. In addition, halogenated vinylidene polymers such as polyvinylidene chloride, butadiene-
Copolymers of conjugated dienes and monovinyl aromatic compounds such as styrene copolymers and isoprene-styrene copolymers, saponified products of copolymers of olefins and vinyl esters such as saponified products of ethylene-vinyl acetate copolymers, or It can also be used for adhesion of acrylonitrile-butadiene-styrene copolymer, especially when used as an adhesive layer for coextrusion molding of a transparent multilayer structure appropriately composed of three or more different synthetic resins mentioned above. A packaging container material with good moldability can be obtained, and its effects can be fully demonstrated. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 Content of ethylene component as intermediate layer: 40 mol%,
A saponified ethylene-vinyl acetate copolymer with a saponification degree of 99.5% and an intrinsic viscosity of 0.092/g is 20 μ thick, and one surface layer has a low density of 0.926 g/cm ³ and a melt index of 2.0 g/10 mm. Melt index 3.2 made of polyethylene with a thickness of 50μ and containing 70% by weight of styrene component as the other surface layer.
g/10mm radial styrene-butadiene block copolymer with a thickness of 380μ, further containing 15% by weight of styrene component as an adhesive layer between each layer, and styrene polymer blocks were arranged at both ends of the isoprene polymer block. 85% by weight of linear isoprene-styrene block copolymer rubber with a melt index of 12g/10mm and 15% by weight of a radial styrene-butadiene block copolymer with a melt index of 2.8g/10mm containing 60% by weight of styrene component. Each of the formulations was coextruded to a thickness of 25 μm using a T-die for multilayer molding to obtain a multilayer sheet with a thickness of 0.5 mm. Here, for the above two types of radial styrene-butadiene block copolymers, epoxidized linseed oil having about 5 epoxy groups in the molecule is used as a binder, and about 5 styrene-butadiene copolymers are used as a binder. A branched polymer block was used. The structure of this multilayer sheet is shown in Table 1, and the measurement results of its various properties are shown in Table 2. Example 2 The content of styrene component as adhesive layer is 25% by weight
Linear isoprene with a melt index of 13 g/10 mm - Radial styrene with a melt index of 3.2 g/10 mm with a styrene block copolymer rubber content of 75% by weight and a styrene content of 70% by weight.
A multilayer sheet was molded in the same manner as in Example 1, except that a blend consisting of 25% by weight of butadiene block copolymer was used. The structure and measurement results of various properties of this multilayer sheet are shown in Tables 1 and 2. Example 3 The content of styrene component as adhesive layer is 35% by weight
Linear isoprene-styrene block copolymer rubber with a melt index of 11.6 g/10 mm, 60% by weight, and radial styrene-butadiene block with a melt index of 2.5 g/10 mm, with a styrene content of 80% by weight. A multilayer sheet was molded in the same manner as in Example 1, except that a blend with 40% by weight of the copolymer was used. The structure and measurement results of various properties of this multilayer sheet are shown in Tables 1 and 2. Example 4 Using the mixture used in Example 2 as the adhesive layer,
A multilayer sheet was molded in the same manner as in Example 1, except that one surface layer was made of polypropylene with a density of 0.915 g and a melt index of 4.5 g/10 mm, and the other surface layer was made of polystyrene with a melt index of 2.5 g/10 mm. . Tables 1 and 2 show the structure and measurement results of various properties of this multilayer sheet. Example 5 A multilayer sheet was molded in the same manner as in Example 1, except that nylon 6 was used as the intermediate layer, and polypropylene and polystyrene were used as the surface layer, respectively, as in Example 4. The structure and measurement results of various properties of this multilayer sheet are shown in Tables 1 and 2. Comparative Example 1 Contains 25% by weight of styrene component as adhesive layer,
Melt index 13g/isoprene polymer block with styrene polymer blocks on both ends
A multilayer sheet was molded in the same manner as in Example 1, except that a 10 mm linear isoprene-styrene block copolymer rubber was used. The structure and measurement results of various properties of this multilayer sheet are shown in Tables 1 and 2. Comparative example 2 Melt index 2.5g/10 as adhesive layer
mm polystyrene 25% by weight and the linear isoprene-styrene block copolymer rubber used in Comparative Example 1
A multilayer sheet was molded in the same manner as in Example 1, except that a blend consisting of 75% by weight was used. The structure and measurement results of various properties of this multilayer sheet are shown in Tables 1 and 2. Comparative Example 3 A multilayer sheet was molded in the same manner as in Example 5, except that the formulation used in Comparative Example 2 was used as the adhesive layer. The structure and measurement results of various properties of this multilayer sheet are shown in Tables 1 and 2.

【table】

[Table] In the Examples and Comparative Examples, the melt index was measured based on JIS K6870.
The various properties of the multilayer sheet shown in the table were measured or judged to be good or bad by the following methods. (1) Transparency...ASTM D1003 (2) Adhesive strength...JIS K6854 (3) Extrusion moldability Extrusion moldability is good if the variation in extrusion rate during coextrusion of a multilayer sheet is less than 10%. It was judged as acceptable if it was 10 to 30%, and unacceptable if it exceeded 30%. (4) Thermoformability Thermoformability was determined using the obtained multilayer sheet, which had a flange with an outer diameter of 130 mm at the top, an outer diameter of 105 mm at the bottom, and a flange with an outer diameter of 105 mm at the bottom.
A bowl-shaped container with a depth of 45 mm and a corrugated cross-sectional wall was vacuum formed, and the slow speed of the molding cycle, uneven thickness of the molded product, and deformation were observed. The molding result was determined to be good if the molding result was obtained, and the molding result was determined to be poor if the molding result was inferior to that.

Claims (1)

[Scope of Claims] 1. Linear isoprene-styrene block copolymer rubber containing 5 to 40% by weight of styrene component.
Radial styrene-butadiene block copolymer 50 containing 90% by weight and 50-85% by weight of styrene component
An adhesive composition containing ~10% by weight. 2 A radial styrene-butadiene block copolymer has the general formula, (S-B)nX (where S is a styrene polymer segment, B is a butadiene polymer segment, and 2. The adhesive composition according to claim 1, wherein the adhesive composition is a copolymer in which the residue of the agent is represented by (n is an integer of 3 or more). 3. The adhesive composition according to claim 1, wherein the linear isoprene-styrene block copolymer rubber is a copolymer rubber having styrene polymer blocks at both ends of an isoprene polymer block.