JPS62220524A - Heat-resistant shrinkable film - Google Patents

Abstract

PURPOSE:To obtain the titled film suitable as a film for forming gathers of paper diaper, by compounding a thermoplastic resin mixture with a silane- grafted polyolefin resin and crosslinking the composition in the presence of a catalyst in air. CONSTITUTION:(A) 100pts.wt. of a composition produced by mixing (i) 20-80wt% thermoplastic resin such as 1,2-polybutadiene and/or polyethylene, etc., with (ii) 80-20wt% aromatic vinyl compound-conjugated diene block copolymer having a molecular weight of 50,000-250,000 is compound with (B) 5-100 pts.wt. of a silane-grafted polyolefin resin produced by grafting preferably 0.01-5.0wt% silane compound of formula (R is olefinic unsaturated hydrocarbon group, etc.; Y is hydrolyzable organic group; R' is R or Y) (e.g. vinyltrimethoxysilane). The obtained composition is added with a silanol condensation catalyst, formed e.g. by T-die extrusion and left standing in air to obtain the objective film.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a heat-resistant stretchable film that has sufficient heat resistance and excellent stretchability.

(Technical background of the invention and its problems) Conventionally, in order to improve the adhesion to the thighs when wearing a disposable diaper, for example, rubber cords, urethane foam, butadiene rubber, and styrene have been used on the side of the disposable diaper where the thighs come into close contact with the diaper. - A mixture of butadiene and styrene block copolymer (hereinafter abbreviated as RB/SBS) is pasted in a stretched state, the tension is removed later, and the elasticity is A method was used in which a certain gear was provided. However, rubber cords and foamed polyurethane are expensive, and although RB/8BS has a considerable advantage over foamed polyurethane in terms of price, it is inferior in heat resistance, so one of the methods for bonding disposable diapers and RB/8B8 is The method of adhering paper diapers to paper diapers using hot melt also had the disadvantage that the film would be cut or punctured, making it impractical.

The above drawbacks also apply when other bonding methods are used.

(Purpose of the Invention) The present invention has been made to eliminate these drawbacks, and the film does not break or become punctured when bonding the film and paper diaper, and therefore has excellent heat resistance. The present invention provides a heat-resistant stretch film.

(Summary of the invention) That is, the heat-resistant stretch film of the present invention comprises (4) butadiene resin and/or polyolein resin 11ii+20
80% by weight of the aromatic vinyl compound-conjugated diene block copolymer, and 80% to 20% by weight of the aromatic vinyl compound-conjugated diene block copolymer. A silane-grafted polyolefin reacted with a silane compound represented by a monovalent hydrocarbon group or a hydrocarbonoxy group, Y is a hydrolyzable organic group, and R' is a pore or a group Y. It is characterized in that a film made of a mixture of 5 to 100 parts by weight of a resin composition is allowed to react with a trace amount of moisture in the presence of a silanol catalyst.

Polyoleain resins include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer ('
JAVA) etc. These resins may be used alone or in combination.
The crystallinity is preferably 85% or more, and if the crystallinity is less than 5%, the strength as a film can be selected from a wide range, but the moldability From the viewpoint of strength as a film, it is preferable that the intrinsic viscosity [η] measured in toluene solution at 30° C. is 0.5 or more and 1, particularly 0.7 to 1.5.

As the aromatic vinyl compound of the aromatic vinyl compound-conjugated diene block copolymer used in the present invention, styrene, α-methylstyrene, etc. are used.

This block copolymer has a molecular weight of 50,000 to 250
．． 000 and the aromatic vinyl compound content is preferably 5 to 50% by weight. If the molecular weight is too high, the moldability will be poor, and if the molecular weight is too low, the strength as a film will be reduced. If the content of the aromatic vinyl compound is more than the above range, the elasticity will be impaired, and if it is less, the strength of the film will be reduced.

There are no particular restrictions on the structure of the block copolymer;
Available for use.

In addition, in the composition (4), the mixing ratio of the thermoplastic resin consisting of butadiene resin and/or polyolefin resin and the aromatic vinyl compound-conjugated diene block copolymer is 20 to 20 for the thermoplastic resin from the viewpoint of moldability and stretchability. 80% by weight
On the other hand, aromatic vinyl-conjugated diene block copolymer 8
0-20% by weight, particularly preferably thermoplastic resin 30-7%
0% by weight, the aromatic vinyl compound-conjugated diene block copolymer is 70 to 30% by weight. The reason for this is that if the weight of the thermoplastic resin is less than 20%, the moldability will be poor;
This is because if the weight R% is exceeded, elasticity will be impaired.

In addition, the composition (2) contains EVA, ethylene/acrylic ethyl acetate copolymer (li:1fA), ethylene/acrylic vinegar copolymer (BAM), or ethylene propylene copolymer (
It is obtained by grafting a silane compound such as vinyltrimethoxysilane (V'I'MO8) or vinylethoxysilane in an amount of 0.01 to 5.0 wt % to a graftable polyolefin resin such as EPR). .

AVA, EEA, EAAc7) VA (BA,
AA) If the content is less than 10% by weight, sufficient adhesion and flexibility cannot be obtained, and if it exceeds 50% by weight, sufficient abrasion resistance and mechanical strength cannot be obtained.
It is preferred to use a range of % by weight.

Further, if the PP content of FiPR is less than 20% by weight or more than 80% by weight, sufficient elasticity cannot be obtained, so it is preferably used in the range of 20 to 80% by weight.

Next, a film consisting of the composition (2) and the composition (to) is treated with a silanol condensation catalyst such as dibutyltin dilaurate or dibutyltin diacetate.
It is crosslinked by leaving it in the atmosphere in the presence of 0 weight percent.

In the present invention, the mixing ratio of the composition (4) and the composition (B) is from 5 to 100 parts by weight of the composition (4) to 100 parts by weight of the composition (4) from the viewpoint of heat resistance and elasticity. Department.

The reason for this is that if the composition of B is less than 5 parts by weight, sufficient heat resistance cannot be obtained, and if it exceeds 100 parts by weight, elasticity is insufficient.

A commonly used mixing method can be used to mix the composition of the present invention, and a conventional melt extrusion molding method such as inflation molding or T-die molding is preferably used as a method for producing a stretch film.

(Example) Examples will be described below.

GP to the composition (4) shown in Examples 1 to 3 and Comparative Example Table. =CM ratio is 9=
The composition (B) prepared in Example 1 was mixed and formed into a film having a thickness of 50 μm using a screw extruder. Next, this film was fixed with a fixing jig, and a 2 mm diameter hot bulb heated to a predetermined temperature in a silicone oil bath was dropped onto the center of the film, and the temperature at which it broke was measured. Also, 50
The film breaking temperature at the time of % stretching was also measured, and the results of the above tests are shown in the same table.

Below margin (*1) -! 1-B820 (trade name of Nippon Gosei Rubber Co., Ltd.) (*2) Califlex (trade name of Aron Kasei Co., Ltd.) (*3) NUO-3195 (trade name of Nippon Unicar Co., Ltd. iVA content 25% by weight) (Effects of the invention ) As mentioned above, in the present invention, a butadiene resin and/or a polyolefin resin, an aromatic vinyl compound, and a silane-grafted polyolefin resin are mixed and crosslinked, so the obtained film has sufficient elasticity and Excellent heat resistance0

Claims (1)

[Scope of Claims] 1. (A) 100 parts by weight of a composition consisting of 20 to 80% by weight of a butadiene resin and/or polyolefin resin and 80 to 20% by weight of an aromatic vinyl compound-conjugated diene block copolymer; B) General formula RR'SiY_2 (where R is an olefinically unsaturated monovalent hydrocarbon group or a hydrocarbonoxy group, Y is a hydrolyzable organic group, and R' is a group R or a group Y) A heat-resistant film comprising a mixture of 5 to 100 parts by weight of a composition comprising a silane grafted polyolefin resin reacted with a silane compound represented by (1) and a trace amount of moisture in the presence of a silanol catalyst. stretchable film. 2. The butadiene resin has a 1,2 bond content of 70% or more, a crystallinity of 5 to 40%, an intrinsic viscosity [η] (30°C in toluene)
2. The heat-resistant stretch film according to claim 1, which is 1,2 polybutadiene having a polybutadiene of 0.7 (dl/g) or more (measured by dl/g).