JPH01141048A - Production of process paper for producing plastic foam - Google Patents

Abstract

PURPOSE:To smoothly release a kraft paper from a urethane foam without the occurrence of release-irregularities, by a method wherein, a permeable base paper and a plastic film are heat-fusion laminated with each other in temporary bonded state. CONSTITUTION:A plastic film layer 3 heat-fusion laminated on a permeable base paper in temporarily bonded state is so constructed as to be releasable from the permeable base paper 2 by a remarkably small release force as shown by an arrow. In a process paper constructed as the above, when a urethane foam A is foam molded with the plastic film layer 3 of a process paper body 1 disposed inside and in contact with the urethane resin or urethane foam, an adhesion strength between the urethane foam and the plastic film is higher than that between the permeable base paper and the plastic film in the process paper. As a result, the plastic film layer 3 adheres and transfers on the surface of the urethane foam A, and the permeable base paper 2 is easily released to be taken up.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a process paper used for manufacturing plastic foam such as urethane foam.

(Prior art) Plastic foams such as urethane foams have conventionally been manufactured by a casting method, but in this manufacturing process, kraft paper has mainly been used as a carrier on which polyurethane resin prepolymers are cast. Ta.

However, when this kraft paper is used, the resin content tends to be impregnated into the kraft paper, and the surface of the urethane foam that is foam-molded adheres strongly to the kraft paper surface, so the kraft paper may peel off from the urethane foam. If the winding cannot be done smoothly and you try to peel it off, the surface of the urethane foam will be peeled off and pieces of urethane foam will stick to the kraft paper, making it impossible to reuse the kraft paper and also destroying the material of the urethane foam product. There were various problems such as the surface of the urethane foam becoming uneven.

Regarding urethane foam engineering paper that solved these problems all at once, the applicant has patented Patent No. 989561
No. 20227] (hereinafter simply referred to as prior art).

To briefly explain the urethane foam process paper according to this prior art, in short, urethane foam is manufactured by extrusion laminating on one side of kraft paper by adjusting the extrusion temperature etc. so that a molten film layer of polyethylene or the like is temporarily attached. This process paper is wound by a predetermined method on the bottom, top, and right and left side wall portions of the space where the urethane foam can be molded, with the film surface facing inward and in contact with the urethane resin or urethane foam. By completely adhering and transferring the film layer to the surface of the urethane foam in a thin film form during foam molding of the urethane foam, only the kraft paper can then be peeled off smoothly and rolled up.
By doing so, the aim is to obtain a urethane foam product. According to this process paper, the resin content does not impregnate the kraft paper, and the urethane foam fragments are not peeled off in an uneven state from the surface of the molded urethane foam, so the yield of urethane foam products based on the urethane resin raw material is reduced. Not only does it have good properties, but the peeled and rolled kraft paper is not impregnated with resin or urethane foam fragments adhere to it, so the kraft paper itself can be reused, making it an innovative product. This brought good news to the urethane foam manufacturing industry as it is a process paper for urethane foam manufacturing.

(Problems to be Solved by the Invention) However, when obtaining the process paper for manufacturing urethane foam according to the above-mentioned prior art, the working conditions, etc. for extrusion laminating the plastic film layer to the kraft paper in a temporarily pasted state, etc. Control is extremely difficult, and the peeling force (in other words, temporary adhesion) of the plastic film to the kraft paper in the resulting process paper is not stable (and tends to vary easily. Therefore, when manufacturing urethane foam, There was also the problem that the kraft paper could not be peeled off smoothly, resulting in uneven peeling.

Therefore, it is relatively easy to manage the working conditions etc. for obtaining this type of process paper, and the peeling force of the plastic film layer against the kraft paper has a stable peeling force (without variations). There has been a desire for a process paper that can be peeled off smoothly from a foam without causing uneven peeling.

(Means for Solving the Problems) The gist of the structure of the method for manufacturing plastic foam process paper according to the present invention to achieve the above object is that the breathable base paper and the plastic film are temporarily pasted together. It is characterized by heat-sealing and laminating the two so that they can form a state.

Here, the air-permeable base paper in the present invention means paper with good air permeability such as kraft paper, and the plastic film is mainly made from polyolefin such as polyethylene or polypropylene by the inflation method and T-die method. It refers to a coated plastic film, and preferably corona discharge treatment is applied to one or both sides of the plastic film for the purpose of improving wettability and adhesion with urethane resin when used as process paper. In addition, the fact that the air permeable base paper and the plastic film constituting the process paper can be temporarily attached means that the adhesive strength between the air permeable base paper and the plastic film layer during the production of polyurethane foam is higher than the adhesive strength between the air permeable base paper and the plastic film layer during molding. This refers to a state in which the adhesive strength between the urethane foam and the plastic film surface exceeds, the plastic film layer adheres and transfers to the urethane foam side, and as a result, the plastic film can be easily peeled off from the breathable base paper. The condition refers to the extent to which the plastic film can be peeled off from the air-permeable base paper surface by hand, smoothly and without uneven peeling. Various methods can be considered as specific means for temporarily adhering the breathable base paper and the plastic film.
For example, when a plastic film is supplied from one side and a breathable base paper is supplied from the other between the nip of a pair of heat rolls and a pressure roll, and the two are crimped together, the heating conditions of the heat rolls, etc. A means is adopted that allows both to be in a temporary bonded state as a result of adjustment. At this time, the working conditions to prevent complete adhesion between the breathable base paper and the plastic film are based on experience: the heating condition is 150 to 200°C, and the pressure condition is 0.
．． 5-3. kg/am is desirable.

Furthermore, since the plastic film used in the present invention is mainly formed by the inflation molding method or the T-die method, operations such as adding a slip agent, tackifier, coloring agent, etc. to the film are easy. This makes it easy to adjust the adhesive force of the plastic film layer of the process paper to the urethane foam to be molded.

(Example) Next, an example of the process paper obtained by the manufacturing method of the present invention will be described based on the accompanying drawings.

Fig. 1 is a partially enlarged sectional view of the process paper obtained by the present invention, and Fig. 2 shows that only the breathable base paper is peeled off when the process paper obtained by the present invention is used as a bottom carrier in the production of urethane foam. It is an explanatory diagram showing a situation simply.

In the drawings, reference numeral 1 indicates the main body of the process paper obtained according to the present invention, 2 indicates an air-permeable base paper such as kraft paper, and 3 indicates a heat-sealed laminated paper in a temporarily attached state on the air-permeable base paper. It is a plastic film layer, and is configured to be peelable from the breathable base paper 2 with an extremely weak peeling force, as shown by the arrow.

As shown in FIG. 2, the process paper having such a structure is arranged so that the plastic film layer 3 side of the process paper body 1 faces inward and is in contact with the urethane resin or urethane foam, and the urethane foam A is When foam molding is performed, the adhesive strength between the urethane foam and the plastic film exceeds the adhesive strength between the breathable base paper and the plastic film in the process paper, so that the plastic film layer 3 is formed on the surface of the urethane foam A. As a result of the adhesion and transfer, the breathable base paper 2 can be easily peeled off and rolled up.

(Function) According to the present invention, it is possible to apply the well-known method of laminating a plastic film and other base materials by heat-sealing lamination, so that the plastic film to be heat-sealed and laminated can be melted. Easy work management by simply setting the surface temperature of the heat roll to a predetermined temperature so that it is heated to a predetermined temperature below the softening temperature, and at the same time setting the associated work conditions (crimping conditions, pressure bonding time, etc.) Process paper in which the breathable base paper and the plastic film are temporarily attached is obtained.

(Effects of the Invention) According to the present invention configured as described above, since the well-known heat-seal laminating method can be applied, it is possible to manufacture by using existing heat-seal laminating equipment as is, and the work conditions can be adjusted. Control is also relatively easy, and the temporary adhesion of the plastic film to the breathable base paper of the resulting process paper is uniform and there is no uneven peeling. Therefore, it is convenient as a process paper for manufacturing plastic foam such as urethane foam. Furthermore, needless to say, since the kraft paper can be smoothly peeled off during the production of the urethane foam, the breathable base paper can also be reused. By selecting the length and width of the breathable base paper and the length and width of the plastic film to be heat-sealed and laminated to it, it is possible to obtain a process paper of the desired length and width, making it possible to produce small lofts. It also has the advantage of making it easy to produce a wide variety of products (processing paper of various lengths and widths).

As described above, according to the present invention, good products of process paper for manufacturing plastic foam such as urethane foam can be stably produced by adopting heat-sealing lamination means instead of the conventional method as a means for obtaining a temporary bonding state. This greatly contributes to the enrichment of technology.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged sectional view of the process paper obtained by the present invention, and Fig. 2 shows that only the breathable base paper is peeled off when the process paper obtained by the present invention is used as a bottom carrier in the production of urethane foam. It is an explanatory diagram showing a situation simply.

Claims (1)

[Claims] A method for producing a process paper for producing plastic foam, which comprises heat-sealing and laminating an air-permeable base paper and a plastic film so that they can be temporarily attached.