JPS6099154A - Molding resin composition - Google Patents

Abstract

PURPOSE:To provide the titled essentially nontoxic composition of high flexibility, strength, heat resistance, transparency and moldability comprising a specific hydrogenated block copolymer, specified polypropylene resin and polybutene-1. CONSTITUTION:The objective composition comprising (a) 30-90 (pref. 40-80) wt% of a block copolymer made up of (i) 10-40wt% of both-end block consisting of aromatic vinyl polymer <=10wt% of which is hydrogenated and (ii) intermediate block consisting of conjugate diene polymer >=90wt% of which is hydrogenated, (B) 5-40 (pref. 10-30) wt% of isotactic polypropylene or a copolymer consisting mainly of the same with a melting point >=150 deg.C, and (C) 5-30 (pref. 10-30) wt% of polybutene-1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to resin compositions. More particularly, the present invention relates to a resin composition that is flexible, has good transparency, high-temperature strength, and moldability, and is non-toxic.

In the past, various resin compositions have been proposed and put into practical use as molding resin compositions for producing transparent and flexible molded products in the fields of food packaging materials, medical instruments, etc. However, all of these have obvious problems with Jy and F.

In other words, molded products made from metal JM of ethylene-vinyl acetate copolymer, ebrene-acrylate copolymer, 1,2-polybutadiene, ethylene-acrylic acid or methacrylic acid copolymer, etc. have poor flexibility and transparency. Although it is good, the tensile strength is 200 Ka/c-I+! No more than the following,
Another problem is that it has insufficient heat resistance, softens at temperatures below 100°C, and cannot maintain its shape. Therefore, the resulting molded product has the disadvantage that it cannot be sterilized by heating at high temperatures. In addition, although plastic polyurethane and thermoplastic polyester have excellent flexibility, tensile strength, and heat resistance, they do not necessarily have sufficient transparency, and if monomer remains, they cause hygiene problems and are expensive. Silicon-based extomers also have excellent flexibility, tensile strength, heat resistance, and transparency, but are luxurious and expensive.

Molded products based on thermoplastic X lastomers such as styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, and styrene-isoprene-styrene block copolymer have excellent flexibility and transparency. Although it is known to have a tensile strength of 200 kQ/cTj or more, it still has insufficient heat resistance and has the problem that it softens even at temperatures below 100°C and cannot maintain its shape.

In this regard, the above copolymers have been improved (hydrogenated block copolymers such as styrene-butadiene-styrene block copolymers and styrene-isoprene-butadiene copolymers have recently begun to be commercially available, but these have improved flexibility, transparency, and tensile strength). Although the strength is excellent and the heat resistance is considerably improved compared to the unhydrogenated product, it is still insufficient, and the flow characteristics of the molten IL are abnormal and the moldability, especially the extrusion moldability, is poor.

Therefore, this block copolymer is only used in the field of engineering plastics by adding small amounts mainly for the purpose of improving the resin.

Furthermore, thermoplastic elastomers based on ethylene-propylene co-compounds and polypropylene are flexible and have relatively good heat resistance, but are significantly inferior in transparency.

On the other hand, molded products using soft polyvinyl chloride are superior in flexibility and transparency, and have a tensile strength of about 200 kQ/d.
In addition, it maintains its shape even at high temperatures of around 120°C and has sufficient strength, so it can be sterilized at high temperatures, and is widely used not only in the general packaging industry but also in food packaging, medical equipment, etc. ing. However, since soft polyvinyl chloride usually contains a large amount of plasticizer, the plasticizer gradually evaporates and hardens, and especially in packaging bags, duvets, etc., the plasticizer transfers to objects that the contents come into contact with. This may cause hygiene problems. In addition, unless the vinyl chloride monomer can remaining in the molded product is extremely reduced, there is a risk of hygienic problems.

Therefore, there has been a desire for a molding resin that satisfies flexibility, strength, heat resistance and transparency, does not contain highly toxic plasticizers or monomers such as flexible polyvinyl chloride, and has good moldability.

The present invention has been made to solve the above-mentioned problems that have been difficult to solve with conventional resin compositions.

The present inventor has achieved flexibility, strength, heat resistance, and transparency by using the hydrogenated block copolymer as the main component, blending it with a specific polypropylene resin, and further combining it with polybutene-1. It was discovered that a substantially non-toxic resin composition with good moldability can be obtained, and as a result of further studies, the present invention was arrived at.

Thus, the present invention provides (a) a block copolymer comprising both end blocks made of a polymer of an aromatic vinyl compound and an intermediate block made of a conjugated diene polymer; A block copolymer in which less than 10% of it is hydrogenated and 90% of the intermediate block is double-hydrogenated. The gist is a molding resin composition consisting of polypropylene or a copolymer containing it as a main component = 5% to 40% by weight, and (C> polybutene-1: 5% to 30% by weight) It is something.

A proposal to include a specific block copolymer used in the present invention as a component of a resin composition is disclosed in JP-A No. 53-124559.
@Publication, JP-A-53-. Publication No. 138451, Japanese Unexamined Patent Publication No. 1973
Publication No. 3-138453, Tokuma 1984-138454@
Publication, JP-A-53-138456, JP-A-53-
138458, JP 53-1384.60, JP 53-138461, etc., but as mentioned above, block copolymers are useful for modifying other resins. It is only used in a relatively small amount as an agent, and the technical idea of modifying engineering plastics is completely different from the idea of the present invention. In other words, the present invention significantly improves the properties of this block copolymer by adding relatively small amounts of specific polypropylene and polybutene-1.

The composite material of this invention has excellent flexibility with a Shore hardness of 45 or less, good transparency with a total light transmittance of 70% or more, and has excellent high-temperature strength and moldability. It has the following. High-temperature strength refers to the shape retention when the sheet is left in an oven at 125°C for 15 minutes, and the strength at this temperature. '4kO
This means that the sheet maintains strength to the extent that it will not break even when a load of /d is applied. In addition, excellent moldability means that injection molding, extrusion molding, and blow molding can be performed using ordinary molding machines.

The resin composition of the present invention satisfies the above-mentioned physical properties, but also has excellent low-temperature properties with a embrittlement temperature of about -70°C, high tensile strength of about 300 kg/cnr, and plasticity. Since it does not contain any additives, it does not cause any sanitary problems, and it also has additional characteristics such as low water absorption ↑1, almost no heating and weight loss, and little change in performance over time.

The composition specified in the present invention is shown within the solid line in FIG. The figure shows the composition ratio of the three components and each vertex A in triangular coordinates.
, B, and C are block copolymers of the present invention [component (
single composition (100% by weight) of polypropylene polymer [component (+1)) and polybutene-1 [component (C)]. All meanings LD, j, F, and G indicate the limit composition of the present invention. That is, the composition composition at each point is (ω, mountain), (C)
D (90°5.5), E (5
5,40,5), F (30°40.30), G (65
, 5, 30>, and the content of the rectangle obtained by sequentially connecting these points becomes the range of the resin composition of the present invention.

The base of the block copolymer used in the present invention is an intermediate block (90 to 60% by weight) made of a conjugated diene copolymer and both end blocks (10 to 40!ffi%) made of a polymer of an aromatic vinyl compound at both ends. ) is a block copolymer consisting of Polystyrene, poly-α-
There are styrene polymers such as methylstyrene, poly-α-methylstyrene, and polychlorostyrene, but those having a number average molecular weight ff of 15,000 to 125,000 are suitable, and polystyrene is the most preferred.

On the other hand, conjugated diene polymers constituting the intermediate block include polybutadiene, polyisoprene, polychloroprene, etc., but their number average molecular weight is 10.
000 to 300,000 are suitable, with polybutadiene and polyisoprene being particularly preferred.

The block copolymer used in the present invention can be obtained by hydrogenating the above block copolymer.

In this case, the hydrogenation ratio of both end blocks must be 10% or less, and the hydrogenation ratio of the middle block must be 90% or more.

Here, the hydrogenation ratio refers to the ratio of double bonds that can be hydrogenated that are actually hydrogenated. In particular, the hydrogenation ratio of the intermediate block is preferably 95% or more. This means that, for example, when the intermediate block is polybutadiene, the hydrogenated product is ethylene-butylene copolymer WI''?i, and when the intermediate block is polyisoprene, the hydrogenated product is ethylene-butylene copolymer WI''?i. This is because the polymer structure improves the heat resistance and weather resistance as a whole, and particularly leads to the excellent heat resistance (high temperature strength) of the composition of the present invention. Both end blocks act as a high hardness component of the thermoplastic extomer, and the middle block acts as a soft component.
If it is less than 0% by weight, hardness and strength will be insufficient, and if it exceeds 40% by weight, flexibility will be insufficient. The content of both end blocks is preferably 15 to 25% by weight.

The block copolymer used in the present invention is Kraton G-
1650, Clayton G-1652. Clayton G-1
657, Clay 1 to G-1658 (all manufactured by Shell Chemical), etc. Moreover, these block copolymers are not limited to one type, and may be used in combination of two or more types.

Next, the polypropylene used in the present invention is isotactic polypropylene having a melting point of 150° C. or higher, or a copolymer mainly composed of it, and those commonly used as molding materials can be used as they are. As the copolymer, block copolymers and random copolymers of propylene and α-olefins such as ethylene and 1-butene can be used, but in order to maintain the flexibility of the composition of the present invention, flexible copolymers are preferred, especially random copolymers. is suitable. Note that the melting point of isotactic polypropylene or a copolymer mainly composed thereof must be 150° C. or higher in order to maintain the high temperature strength of the composition of the present invention. In the present invention, the effect of this polypropylene component on the composition of the present invention is mainly in improving high temperature strength, but in combination with the presence of polybutene-1, which will be described later, it has the effect of improving the moldability of the composition. It is thought that the The block copolymer of the present invention alone can be used as pellets 1 for immediate use.

It is difficult to manufacture tubes, sheets, etc., and it is also difficult to mold bottles, etc. by blow molding, but the coexistence of the polypropylene component and the polybutene component significantly improves moldability. Another great advantage of the polypropylene component is that it has good compatibility with block copolymers and can be used to form polyblends with good transparency.

Next, the effect of the polybutene-1 component in the composition of the present invention is thought to be the improvement of moldability and maintenance of low-temperature flexibility, etc. It is a great effect that the transparency of the polyblend group of the polypropylene component is further improved. It also has the advantage that the content of expensive block copolymers can be reduced due to its increased flexibility. In addition, the resin composition of the present invention has superior low-humidity flexibility and high-temperature strength compared to a similar ethylene-vinyl acetate covalent polymer.
Furthermore, compared to the case where an ethylene-acrylate copolymer is used, it has less hydrolyzability and less odor.

The range of the main component resin composition of the present invention is shown in FIG. 1, and it is necessary that the block copolymer has a content of 30% by weight or more and 90% by weight or less. If it is less than 30% by weight, the flexibility and transparency will be insufficient, and if it is more than 90% by weight, the high temperature strength and moldability will be insufficient. Particularly preferred is 40% by weight or more and 80% by weight or less. The polypropylene component must be 5% by weight or more and 10% by weight or less. If it is less than 5% by weight, the high temperature strength and formability will be insufficient.
If it is more than 0% by weight, flexibility and transparency will be insufficient. Particularly preferred is 10% by weight or more and 30% by weight or less. The content of polybutene-1 must be 5% by weight or more and 30% by weight or less.

If it is less than 5% by weight, the moldability, flexibility and transparency will be insufficient, and if it is more than 30% by weight, the high temperature strength and transparency will be insufficient. Particularly preferred is a block copolymer of 1° with a weight content of 10 C1i fit% or more and 30 weight% or less;
0 inm%, mountain) isotactic polypropylene fork (J copolymer mainly composed of it: 10 to 30 weight 17
1%, and (C) polybutene-1: 10-30%
The resin composition consisting of the above composition has particularly good flexibility, transparency (11), high-temperature strength and moldability, and has a preferable composition in the range '4U'.

The composition of the present invention has the above-mentioned essential main resin components, flexibility, transparency, 1 (1), and bJ plastics (width) of B1 (width) to the extent that it does not impair high temperature strength, moldability, and safety. , antiblocking agent, seal 1i:1 improver, heat stabilizer,
It has the ability to contain antioxidants, ultraviolet absorbers, lubricants, crystal nucleating agents, coloring agents, etc.

However, when used as a food packaging material or a medical device, it is preferable not to add additives such as plasticizers.

The composition of the present invention can be molded in a conventional manner.

That is, depending on the formulation of the composition, mixer,
After mixing with a blender, etc., knead further with a hot roll and press to create Sheet 1~, or use an extruder to create Repellets 1~ and extrude sheets, blocks, odd-shaped products, Chicove, nets, etc. It can also be molded. Also, various parts, bottles, etc. can be made from the pellets by injection molding or blow molding. 1. Various molded products can also undergo secondary processing such as cutting, painting, adhesion, and printing.

The composition of the present invention has various characteristics as described in W, so it can be used in the fields of industrial materials, household goods, etc., but in particular, it has high high temperature strength and non-toxicity. It has a wide variety of uses in the fields of food packaging materials and medical instruments that require high temperature sterilization. More particularly, the composition □ of the present invention is characterized by its high degree of flexibility, transparency, high temperature strength,
It is particularly suitable for making medical bags such as blood bags, infusion bags, and artificial dialysate bags due to its moldability and sanitary safety.

The present invention will be explained below with reference to examples, but it goes without saying that the present invention is not limited to these examples.

Example 1 Clay 1 to G-1650 (
(manufactured by Shell Chemical) and Kraton G-1657 (manufactured by Shell Chemical), a random copolymer with a melting point of 165 ° C. (this random copolymer has an ethylene content of about 5%) as polyb Ll pyrene, and A, A, and polybutene 0400 (manufactured by Adeka Argus) were used as polybutene-1, and their compositions were changed and mixed.
Bare sheets 1 to 1 were made using two rolls, and this was molded into L [cotton] to make various sheets with a thickness of about Q and 4 mm, and their physical properties were measured. The measurement results (2) are shown in Table 1. In addition,
Tensile strength and elongation are JIS K6732, total light transmittance is A
STMD-10Q3, Shore hardness is ASTM D-17
IC0 or high-temperature strength is measured according to 06, and the shape retention when Seat 1~ is left in an oven at 125°C for 15 minutes, and the change in Sheet 1~ when a load of C1.4Kg/GIF is applied at this temperature. It is a measurement of shape love.

Clayton G-1650 and Clayton G-1657 used in the examples have polystyrene blocks at both ends and a copolymer of ethylene and butylene in the central hydrogenated block, and the ratio of the former to the latter is 1650, which is 28/72.1657. is 14
/86.

(The following is a margin, continued on the next page) It is clear from the table that J: Uni, the physical property values of the resin composition of the present invention are extremely) 51 should be added.

[Brief explanation of drawings]

FIG. 1 is a triangular coordinate graph showing the composition of the resin composition of the present invention. Figure 1

Claims (1)

[Claims] (1) (a) Copolymerization of both 9M biblocks of a block copolymer consisting of both end blocks consisting of F aromatic group, vinyl, compound, and heavy p-form and an intermediate block consisting of a conjugated diene system and polymer. 5. The intermediate block is composed of 10 to 40% by weight, less than 10% of which is hydrogenated, and the intermediate block is hydrogenated at least 90%. Horn common combination: 30% by weight to 90% by weight,
,. Isotactic polyb [l pyrene or a copolymer mainly composed thereof: 5% to 40%, and −3°% polybutylene, 71. : A resin composition for molding consisting of 5% by weight and 30% by weight. Block copolymer (a): 40-80 tt's f
a%, (1)) isotactic polypropylene or a copolymer containing it as the main component = 10 ~; 30 weight Ii%
, and (C) polybutene-1: 10 to 30 wt 71%
A molding resin composition according to claim 1, comprising: