JPS5844464B2 - Libatsuki Enshin Film no Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a film having ribs, and more particularly, to a method for producing a stretched film having ribs having excellent physical properties such as tear resistance.

It is generally known that the physical properties of plastic films can be improved by stretching, and plastic films with improved physical properties such as tensile resistance and impact resistance are used for packaging, miscellaneous goods, and agricultural purposes. There is.

However, although such stretching treatment improves the physical properties of the film such as tensile resistance and impact resistance, it has the disadvantage of decreasing the tear strength of the film, making it difficult to obtain a film that satisfies all points.

For this reason, composite films have been developed and utilized.

For example, there have been proposals for laminating a stretched film and a non-stretched film, a stretched film and a fibrous material, or a stretched film and a net-like material. Because the manufacturing method for laminated filtration is complicated, it is inevitably expensive, and because it is laminated by adhesion or fusion, it is difficult to obtain sufficient strength.
From the viewpoint of industrial implementation, it could not necessarily be said that the film was satisfactory.

For this reason, JP-A-49-69776 and JP-A-49
A patterned stretched film was proposed as described in Japanese Patent No. 105863.

The former involves embossing and biaxially stretching a polypropylene film under specific conditions.

This method relates to a method for producing an oriented film without holes, and according to this method, it is possible to obtain a film with a special pattern whose tear strength is certainly improved compared to a biaxially oriented smooth film.

However, since the film has a continuous valley pattern, it cannot be expected to have sufficient physical properties such as tensile resistance and impact resistance.

Moreover, the molding in this method is based on the distorting method of embossing using a cold roll;
Since the method uses a method of stretching a sheet with continuous thin valleys, it has the disadvantage that it can only be manufactured within a very limited range of specific conditions.

On the other hand, the latter is achieved by continuously passing the plasticized film obtained by extrusion between a forcedly cooled vertically grooved roll and a flat roll, as well as between a similarly forcedly cooled horizontally grooved roll and a flat roll. proposed a method of forming lattice-like ribs on the film surface and then biaxially stretching without heating to obtain a stretched film with lattice-like reinforcing ribs.

The stretched filtrate obtained by this method differs from the former one in that it has a continuous structure of patterned lattice-like ribs, making it relatively easy to stretch and providing superior strength. In method ζ, the lattice-like ribs are patterned on only one side, and the intersecting portions of the ribs have the same thickness as the ribs, so the tear resistance is not sufficient.

On top of that, in order to perform molding in two stages, the vertical ribs obtained by the front rolls are crushed by the rear rolls, making it impossible to obtain a sufficient rib structure, and molding is performed using cooling rolls. The manufacturing method itself has its own problems, such as increased distortion due to the method of stretching while heating.

In view of the current situation, the present inventors have completed the present invention as a result of repeated research on a method for manufacturing a stretched film that is inexpensive and has excellent toughness. A number of straight or serpentine ribs are arranged in parallel relation on one side of the film, and a number of straight or serpentine ribs are arranged in parallel relation within the reflection of the film so as to intersect with the ribs and form a rib crossing portion. The temperature of the rib portion of the film is the same as or lower than that of the entire surface of the light, and the film is biaxially stretched at a stretching temperature that is 10°C or more lower than the temperature for forming or molding the ribs. By doing so, there is provided a method for producing a ribbed stretched film characterized by comprising a biaxially oriented film portion, a -axis oriented rib portion and a non-oriented rib crossing portion.

In order to make the present invention easier to understand, the present invention will first be explained based on the drawings. Figures 1-1 are plan views, and Figures 1-1 are plan views.
Figure 2 is a longitudinal sectional view taken along line A-A' in Figure 1-1;
1-3 are longitudinal cross-sectional views taken along the line BB'.

Figure 21 and Figure 2-2 show the ribbed film shown in Figure 1-1 biaxially stretched, Figure 2-1 is a plane, and Figure 2-2 is a portion of the stretched film. FIG.

FIGS. 3 and 4 show films other than the film shown in FIG. 1-1 in which straight ribs obtained by carrying out the present invention are in a parallel relationship; An example of a combination with diagonal ribs is shown.

In Figures 1-1, 1-2, and 1-3, 1 is a film part, 2 is a surface rib molded or molded on the surface of the film, and 3 is a rib molded or molded on the back side of the film. The back rib 4 is a rib crossing portion where the front rib 2 and the back rib 3 intersect.

1' in Figure 2-1 indicates Figure 1-1, Figure 1-2, and Figure 1-1.
The ribbed film shown in Figure 3 is biaxially stretched so that film part 1 is biaxially oriented, and 2' and 3' are the same surface ribs as shown in Figures 1, -, and -1. The portions corresponding to 2 and back ribs 3 respectively indicate uniaxially oriented rib portions, and 4' similarly indicates a non-oriented rib crossing portion where the rib crossing portion 4 remains almost unoriented. .

Next, in order to make the present invention easier to understand, the present invention will be explained in detail with reference to the above drawings.

A suitable method for obtaining a filter in which linear ribs shown in FIGS. 1-1, 1-2, and 1-3 are molded or molded in parallel relationship is, for example,
Examples include a method for producing a net-like ribbed film as described in the publication, or a continuous press method having a mechanism for forming while moving a mold for producing the ribbed film.

The film obtained by these methods is then biaxially stretched, but the stretching temperature is set at a temperature different from that of the ribbed film, since mold reversion may occur during stretching and it may not be possible to obtain a film that fully possesses the effects of the present invention. It is necessary to prevent mold return by lowering the temperature by at least 10°C lower than the temperature during molding or molding.
It is necessary to maintain the temperature of the rib-intersecting portion 3 and the rib-crossing portion 4 to be approximately equal to or lower than that of the film portion 1, and by biaxially stretching the ribbed film under such temperature conditions, Biaxially oriented film portion 1', -axis oriented rib portions 2', 3 shown in FIGS. 2-1 and 2-2
A specially oriented film with ribs can be obtained, which is composed of the non-oriented rib crossing portions 4' and 4'.

The reason why such a stretched film can be obtained is 1-1.
In the process of stretching the ribbed film shown in Figures 1-2 and 1-3, first considering the lines of force in the BB' line, Due to the difference in thickness, the rib portions are stretched in the BB' line direction, but the rib crossing portions are hardly stretched.

Next, in the line of force in the AA' line direction, due to the difference in thickness between the film part and the rib part, the film part is stretched in the AA' direction, but the rib part is hardly stretched.

A″-A″ line and B″-B/ perpendicular to these lines of force.
//The same thing can be said about the lines of force in the linear direction, so
Taking all of these into consideration, the film part is biaxially oriented, the rib part is uniaxially oriented only in the longitudinal direction without being stretched in the width direction, and the rib crossing part remains unstretched and has no orientation. Conceivable.

In a stretched film to obtain such an orientation, the ribs do not necessarily have to be orthogonal as shown in FIG.
It should be understood that serpentine or diagonal ribs, such as those shown in FIGS. 3 and 4, may also be used.

The ribbed stretched film obtained by the present invention is strong against impact because the film portion is biaxially oriented, strong against tension because the rib portion is uniaxially oriented, and has unoriented rib crossing portions. Therefore, even if a tear notch occurs in the film portion, the notch will propagate to one of the ribs surrounding the film portion, and then be torn along the longitudinal direction of the rib, but the unoriented rib intersection portion Since the film stops when it reaches , the entire film is not torn, so it is easy to repair, and the film has significantly improved tear strength compared to conventional films.

In addition, the ribs are not one-sided lattice-like ribs, but are separated on both sides of the film, and are arranged in the same direction, making it easy to remove deposits and other dirt from the film.Especially when used for agricultural covering materials, the film Dirt on the outer surface is easily washed away by rain, and water droplets adhering to the inner surface also flow down smoothly, which is a significant practical effect.

The resin used in the present invention is a thermoplastic resin that can be extruded and stretched, such as polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene (ABS).
Suitable resins include styrene-acrylonyl (As) resin, ethylene-vinyl acetate copolymer resin, polyolefin, polymethyl methacrylate, and polycarboyte.

Next, the present invention will be explained with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 Vinyryoku 37M (Product name: Vinyl chloride resin manufactured by Mitsubishi Monsanto Chemical Co., Ltd., straight polymer, average degree of polymerization 80
0) A resin composition obtained by kneading 100 parts by weight, 4 parts by weight of a stabilizer, and 1 part by weight of a lubricant in a Henschel mixer was mixed using an extruder with a cylinder diameter of 40X, and the rear part of the cylinder was 160 mm.
A flat film having a thickness of IX was produced by extrusion at a screw rotation speed of 4 Or, p, m under temperature conditions of 180° C. in the middle, 198° C. in the front, and 200° C. in the flat die.

The flat film was formed into a double-sided ribbed film as shown in FIGS. 1-1, 1-2, and 1-3 by hot pressing at a press temperature of 200°C.

As for the film dimensions, the thickness of the film part is 0.7%, and the thickness of the rib part is ``%s!The thickness of the J-shaped intersection part is 2.1%.
, the width of IJ is IXs! The length from the center of the J-shaped rib to the center of the adjacent rib (hereinafter referred to as "rib spacing") was set to 10%.

Next, the ribbed film was stretched at a stretching temperature of 100°C and a stretching ratio of 2.
The wall thickness of the film portion of the ribbed stretched film obtained by biaxially stretching using a test stretching machine was approximately 0.16%.
, the wall thickness of the IJ section is approximately 1.1%, and the wall thickness of the IJ section crossing section is approximately 2.1%. It was OX.

As a result of measuring the thousand-plane birefringence using a Nippon Kogaku POH type polarizing microscope, the film part 2.1X10-'rib part 2
1.2 x 10-', rib intersection 1.0 x 10-4
Met.

Furthermore, when a notch was made in the film portion and the film was torn by hand, the tear line bent in the longitudinal direction of the rib portion at the rib portion, stopped at the rib replacement portion, and did not come out of the mesh.

Comparative Example 1 Using the same extruded film as in Example 1, press temperature 2
A press film with lattice-like ribs on one side was formed by hot pressing at 00°C.

The film dimensions are the same as in Example 1, the thickness of the film part is O-7', the thickness of the rib part is '-4%z', the thickness of the J-blade crossing part is 2, xz, and the width of the IJ-b is 1. %, and the rib spacing was 10%.

Next, the ribbed film was biaxially stretched using a test stretching machine under the same conditions as in Example J, and the thickness of the film portion of the ribbed stretched film obtained was approximately 0.16 mm. Approximately 1.1%, and the thickness of the rib intersection area is approximately 1.1%. It was L%.

Next, as in Example 1, the plane birefringence was measured. As a result, the film part was 2.5 x 10-' and the rib part was 20.3 x 1.
．． O-4, the rib crossing portion was 2.3×10-'.

Further, when a tear test was conducted in the same manner as in Example 1, the tear line easily passed through the rib intersection portion and showed a tendency to run along the rib.

Comparative Example 2 The same extruded film as in Example 1 was continuously passed between a cold metal roll and a cold smooth roll in which grid grooves of the same dimensions as in Comparative Example 1 were carved, to form a one-sided grid pattern. When a ribbed film was formed and stretched under the same conditions as in Example 1, mold reversion occurred and no stretched film was obtained.

[Brief explanation of drawings]

Figures 1-1, 1-2, and 1-3 are examples of filters obtained by carrying out the method of the present invention, in which linear ribs are formed or molded in parallel relationship, and show the film before stretching. show. Figure 1-1 is a plan view, Figure 1-2 is a vertical sectional view taken along line AA' in Figure 1-1, and Figure 1-3 is a 13-
It is a longitudinal cross-sectional view along the B' line. Figures 2-1 and 2-2 show the ribbed film shown in Figure 1-1 after biaxial stretching;
FIG. 2-1 is a plan view, and FIGS. 2-2 are partial perspective views. FIGS. 3 and 4 show an example of a combination of parallel ribs obtained by carrying out the present invention in a linear relationship and a serpentine rib and a diagonal rib. 1 is a film part, 2 is a front rib, 3 is a back rib, 4 is a rib crossing part, 1' is a biaxially oriented film part, 2' is a uniaxially oriented front rib part, 3' is a uniaxially oriented back rib part, 4
′ is the unoriented rib replacement part.

Claims (1)

[Claims] 1 One side of a thermoplastic synthetic resin film has a large number of linear or serpentine ribs in parallel relationship, and the opposite side of the film has a large number of linear or meandering ribs that intersect with the ribs and form a rib crossing portion. The serpentine ribs are formed or molded in a parallel relationship, and then the temperature of the rib portion of the film is the same as or lower than that of the entire surface of the film, and is lower than the molding or molding temperature of the ribs. Production of a ribbed stretched film characterized by biaxially oriented film portions, uniaxially oriented rib portions, and non-oriented rib crossing portions, by biaxially stretching at a stretching temperature 10° C. or more lower. Law.