JPH0263057B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinyl chloride resin inflation film with good opening properties and a method for producing the film. Many thermoplastic resins are used in inflation film because it requires only bottom adhesion for bag making, and slip agents and anti-blocking agents are added to improve the opening of the film. PVC resin is often used in hard and flexible sheets and films due to its many advantages such as clear transparency, supple flexibility, good mechanical properties, and relatively low price when combined with a plasticizer. It is being However, soft sheets and films have disadvantages such as oozing of plasticizer called bleed, which causes adhesive agglomeration (blocking) of the film, and their use in bags is limited due to their openability. That is, although bags made of blown film are often used with automatic packaging machines, blown film made of soft vinyl chloride can hardly be used with automatic packaging machines because of this drawback. The first object of the present invention is to improve the opening properties of soft PVC blown film, which could not be solved by conventional techniques such as adding a slip agent, and to create a blown film for bag making that can be used in automatic packaging machines. The second object is to provide a method for producing the same film. The first aspect of the present invention is a vinyl chloride-based resin inflation film in which a two-color extruded tubular film having two types of film portions having approximately equal areas is flattened with a fold near the boundary between the two types of film portions, The raw material composition for one kind of film part is a soft and transparent blended composition based on ordinary vinyl chloride resin, and the raw material composition for another kind of film part is polyether glycol diacrylate or dimethacrylate, polyester. One or more comonomers selected from glycol diacrylate or dimethacrylate, allyl acrylate or allyl methacrylate
It is characterized by being a soft matte compounded composition whose base resin is a vinyl chloride copolymer consisting of 0.05 to 0.5% and 99.95 to 95% of vinyl chloride. The second aspect of the present invention is to manufacture a blown film using a two-color extrusion method in which two extruders are used to extrude different types of vinyl chloride resin compositions from each extruder to the same die. Obtained by extruding approximately equal amounts of a soft transparent compound composition based on a regular vinyl chloride resin from one extruder and a soft matte compound composition based on a vinyl chloride copolymer from the other extruder. This is a method for producing a blown film with good opening property, which is characterized in that a tubular film is rolled up flat by pinch rolls with a crease near the boundary between two types of film parts. More specifically, the vinyl chloride copolymer that is the base resin of the soft matte compound composition that is one of the materials is diacrylate or dimethacrylate of polyether glycol, diacrylate or dimethacrylate of polyester glycol,
One or more comonomers selected from allyl acrylate or allyl methacrylate 0.05~
5% and 99.95-95% vinyl chloride. The present invention will be described in more detail below. The soft transparent compound composition, which is one of the materials of the film, consists of 100 parts by weight of a regular vinyl chloride resin, 20 to 200 parts by weight of a plasticizer, 1 to 5 parts by weight of a stabilizer, and other materials usually used to modify vinyl chloride resin. Various additives, such as ultraviolet absorbers, antioxidants, lubricants, etc., are appropriately blended according to the purpose of the film. A normal type of vinyl chloride resin is a vinyl chloride resin with an average degree of polymerization of 500 to 3000, and it also includes vinyl chloride containing 85% or more of vinyl chloride, vinyl esters such as vinyl acetate, alkyl vinyl ethers, acrylic esters, and methacrylic acid. It may also be a copolymer with ester, vinylidene chloride, monoolefin, etc. As the plasticizer, one type or two or more types of plasticizers such as phthalic acid ester type, fatty acid ester type, phosphoric acid ester type, trimellitic acid ester type, polyester type, and epoxy ester type can be used in combination. Stabilizers include Isuzu type, Cd-Ba type, Ba-Zn
One type or two or more types of stabilizers such as Ca-Zn type and Ca-Zn type can be used in combination. The other material, the soft matte compound composition, is composed of 99.95 to 95% vinyl chloride, diacrylate or dimethacrylate of polyether glycol with an average degree of polymerization of 2 to 100, and diacrylate or dimethacrylate of polyester glycol with an average degree of polymerization of 2 to 100. The base resin is a vinyl chloride copolymer consisting of 0.05 to 5% of one or more polyfunctional comonomers selected from methacrylate, allyl acrylate, or allyl methacrylate.
To 100 parts by weight, add 20 to 200 parts by weight of a plasticizer similar to that used in the transparent blended composition, 1 to 5 parts by weight of a stabilizer, and other additives and pigments depending on the use of the film. It contains 0 to 10 parts by weight of a filler such as calcium carbonate. The vinyl chloride copolymer of the base resin of the matte formulation contains 99.95 to 95% vinyl chloride, polyethylene glycol, polypropylene glycol, and polyethylene glycol.
Average degree of polymerization of 1,3-butylene glycol, polytetramethylene ether glycol, etc. 2-100
diacrylate or dimethacrylate of polyether glycol, diacrylate or dimethacrylate of polyester glycol with an average degree of polymerization of 2 to 100, such as polyneopentylene adipate glycol, polyfunctional comonomer such as allyl acrylate, allyl methacrylate, etc. 0.05 to 5%
It can be obtained by copolymerizing these by a conventional suspension polymerization method. The content of these polyfunctional comonomers is 0.05%
In the following cases, the matte film obtained using the vinyl chloride copolymer as a base resin will not have a sufficient matting effect, and the opening property of the blown film produced by the production method of the present invention will also be poor.
Furthermore, if the comonomer content exceeds 5%, the surface of the film may exhibit a shark-skinned appearance, and the dimensional stability during inflation may become unbalanced with the transparent film, resulting in poor processability, making it impractical. It disappears. Furthermore, if copolymers with comonomers other than those listed here, such as diallyl phthalate and triallyl cyanurate, which are commonly used to modify vinyl chloride resins, are used, the processability will be extremely poor, resulting in thin blown materials. The film cannot be molded, or even if it is forcibly molded, the surface of the film has a shark's skin appearance or a rough texture, resulting in a product with no commercial value. The vinyl chloride soft transparent blended composition and soft matte blended composition of the film materials of the present invention may be in the form of powder or granules as long as they are sufficiently and homogeneously mixed. The two-color extrusion method used in the present invention is a conventional method in which two single-screw, twin-screw, or multi-screw extruders are combined, and the matte compound is passed from the horizontally placed extruder to the vertically placed extruder. transparent formulation from the extruder,
It is desirable to extrude approximately equal amounts into the two-color ring dies, but the reverse is also acceptable. There is no particular restriction on the size of the extruder, but it is desirable that the two extruders be of equal size, and the inner diameter of the cylinder of the extruder is preferably about 30 to 90 mm. The extruded tubular film is air-cooled or water-cooled, folded near the boundary between the transparent film portion and the matte film portion, and then flattened and wound up using pinch rolls.
If the mesh occasionally deviates significantly from the boundary, the area in which the transparent film portions of the wound film come into contact with each other increases, resulting in extremely poor opening properties. It is also desirable to extrude the tubular film so that the transparent part and the matte part are approximately equal in area.
If the area of the transparent portion becomes too large, the transparent film portions may come into contact with each other after winding, resulting in blocking, which will impair the opening properties of the bag. The bags obtained from the vinyl chloride resin blown film produced according to the production method of the present invention have significantly improved opening properties compared to bags made from conventional soft vinyl chloride blown films. It can be used in an automatic packaging machine.
Especially when used in an automatic packaging machine that holds the bag almost horizontally and inserts the packaged items from the side, holding the bag with the matte film side down will allow the packaged items to slide smoothly over the bag. The advantage of sliding inside becomes noticeable. Conventionally, PVC film bags for this purpose had to be made by fusing an embossed soft film and a transparent film at their peripheral parts, which was not practical due to bag manufacturing costs, but the present invention can be used. In particular, it can be said that it has been possible to make bags from soft PVC film for automatic packaging at low cost through a simple process. EXAMPLES Next, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Example 1 Two 40mmφ single screw extruders (manufactured by Japan Steel Works, L/
D=25) was produced by a two-color extrusion method using a cloth combination, and the appearance and opening properties of the film, as well as the moldability during inflation, were evaluated. The results are shown in the table. The opening property of the film was evaluated as follows.
The length of a flattened film in the winding direction
When a 20 cm piece is cut, held between the palms of both hands, and the two types of film sides are shifted from each other in a direction perpendicular to the winding direction, the two types of film sides are easily peeled off and both ends of the tubular film are opened. 〇, and those where the two types of film surfaces do not separate from each other are marked ×. For the evaluation of moldability, a film with good dimensional stability where there is almost no difference in the elongation of the two film parts during inflation is rated as 0, and a film with a marked difference in elongation between the two film parts or Items that cannot be molded are marked as ×. The material for the first extruder (soft transparent compound composition) was vinyl chloride homopolymer (Chitsuso) with an average degree of polymerization of 1030.
(manufactured by Adeka Argus Chemical Co., Ltd.) 100 parts by weight, 50 parts by weight of di-2-ethylhexyl phthalate, 2.5 parts by weight of Ba-Zn composite stabilizer (manufactured by Adeka Argus Chemical Co., Ltd.),
100% composition consisting of 3.0 parts by weight of epoxidized soybean oil
After blending with a Henschel mixer (manufactured by Mitsui Miike Seisakusho), a 65mmφ extruder (manufactured by Japan Steel Works)
This is a pellet compound obtained by granulation. The material for the No. 2 extruder (soft matte compound composition) was vinyl chloride 99.9% instead of vinyl chloride homopolymer.
% and 0.1% polyethylene glycol diacrylate with an average degree of polymerization of 14 was used as the base resin, but the same plasticizers, stabilizers, etc. were mixed in the same proportion as the material of the first machine. It is a pellet compound obtained by blending and granulating in the same manner. Examples 2 to 6 and Comparative Examples 1 to 5 Inflation was carried out in the same manner as in Example 1, except that the base resin of the material for No. 2 extruder was the vinyl chloride copolymer or homopolymer shown in the table. A film was made and evaluated in the same manner as in Example 1.
The results are shown in the same table. 【table】

Claims (1)

[Scope of Claims] 1. A vinyl chloride resin inflation film in which a two-color extruded tubular film having two types of film portions having approximately equal areas is flattened with a fold near the boundary between the two types of film portions, The raw material composition for one kind of film part is a soft and transparent blended composition based on ordinary vinyl chloride resin, and the raw material composition for another kind of film part is polyether glycol diacrylate or dimethacrylate, polyester. A vinyl chloride copolymer consisting of 0.05 to 5% of one or more comonomers selected from glycol diacrylate or dimethacrylate, allyl acrylate, or allyl methacrylate and 99.95 to 95% of vinyl chloride is used as a base resin. A vinyl chloride resin inflation film that is a soft matte composition. 2. In the production of blown film using a two-color extrusion method in which two extruders are used to extrude different types of vinyl chloride resin compositions from each extruder to the same die, one extruder extrudes a normal type of vinyl chloride resin composition. A soft transparent compound composition based on resin,
From the other extruder, 0.05 to 5% of one or more comonomers selected from polyether glycol diacrylate or dimethacrylate, polyester glycol diacrylate or dimethacrylate, allyl acrylate or allyl methacrylate, and vinyl chloride 99.95%. A tubular film obtained by extruding approximately equal amounts of a soft matte composition based on a vinyl chloride copolymer consisting of ~95% is pinched with a crease near the boundary between the two film parts. A method for producing an inflation film with good opening properties, which is characterized by rolling it and winding it up as a flat film.