JPH11235797A - Carrier film for smc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier film for SMC which enables an easy peeling operation to be performed on an upper carrier film and a lower carrier film and a resin compound during molding the SMC, and at the same time, ensures the qualitative stability of the SMC and the improvement of working environments. SOLUTION: The carrier film 1 for SMC which sticks to the upper and lower faces of a resin compound during manufacturing the SMC is a multi-layer composite film comprising at least, a polypropylene layer 3, a polyethylene layer 2 and a polyamide layer 4, laminated on each other. The film 1 has a thickness to be adjustable to the thickness of 20-100 μm and has the polyethylene layer 2 to be positioned at a face which comes into contact with the resin compound, so that the peel operating properties of the carrier film with the resin compound are upgraded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier film for an SMC (sheet molding compound), which sandwiches a resin compound during the production of the SMC.

[0002]

2. Description of the Related Art Conventionally, in SMC, a carrier film is fixed to upper and lower surfaces in order to suppress the permeation of styrene from a resin compound. The compound is cut into an arbitrary size, filled in a press as a molding material, and press-molded.

[0003] As a carrier film used in the production of SMC, a single layer of polypropylene film has been used.

[0004]

As described above, the conventional S
Since the carrier film used for the production of MC is a single layer of polypropylene film, when the upper and lower carrier films are peeled off, the resin compound and the carrier film come into close contact with each other, and the peeling operation is extremely troublesome.

[0005] If a polyethylene film having a good film releasability is used as a carrier film in consideration of the releasability, the peeling operability is improved, but the polyethylene film has low physical properties.
When the SMC is manufactured, the film stretches, and in order to supply SMC of stable quality, the thickness of the carrier film must be increased, resulting in an increase in cost.

Further, in the conventional polypropylene film, there is a problem that styrene in the resin compound tends to permeate, and if the SMC is left untreated, the stability of the quality and the working environment deteriorate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. In manufacturing an SMC, in order to sandwich the resin compound, an SMC which is tightly laminated above and below the resin compound is provided.
An object of the present invention is to provide a carrier film for SMC that can easily peel off the upper and lower carrier films and the resin compound during the formation of SMC, and can improve the stability of SMC quality and the working environment. I do.

[0008]

In order to achieve the above-mentioned object, the present invention is directed to an SMC carrier which is adhered and laminated on upper and lower surfaces so as to sandwich the upper and lower surfaces of a resin compound during SMC production. In the film, the carrier film is formed of a multilayer composite film of at least three or more layers obtained by laminating layers of polypropylene, polyethylene, and polyamide.

The invention according to claim 2 is characterized in that the carrier film is provided with a polyethylene layer on a contact surface with a resin compound.

[0010] The invention according to claim 3 is characterized in that the film thickness is 20 to 100 µm.

As is apparent from the above constitution, as an SMC carrier film sandwiching a resin compound,
Use of a multi-layer composite film of at least three layers laminated with polypropylene, polyethylene, and polyamide layers provides good application stability, low styrene transmittance, and improves SMC quality stability and work environment. it can.

According to the second aspect of the present invention, by using the polyethylene layer on the contact surface with the resin compound, the peeling operation between the resin compound and the carrier film becomes very easy during SMC molding.

According to the third aspect of the present invention, if the film thickness is at least 20 μm, the styrene transmittance and the working environment can be better maintained. One more
Thicknesses greater than 00 micron meters are costly and do not change much in performance.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of an SMC carrier film according to the present invention will be described in detail with reference to FIG.

FIG. 1 is a cross-sectional view showing a schematic structure of a five-layer carrier film 1 which is an embodiment of the carrier film for SMC according to the present invention.
It has a configuration in which a polypropylene layer 3 is laminated on each inner side and a polyamide layer 4 is laminated in the center, and the thickness is adjusted to 20 to 100 microns.

The polyethylene and polypropylene used in the present invention, even if they are copolymers with other resins such as ethylene, propylene, butene, isoprene, pentene and methylpentene, may be vinyl acetate, ethyl acrylate, ionomer, diene chloride, or the like. A copolymer such as vinyl may be used. As the polyamide, polyamide 4, polyamide 6, polyamide 7, polyamide 8, polyamide 9, polyamide 9, polyamide 11, polyamide 12, polyamide 6-6, polyamide 6-10 and the like can be used. -6 is widely used and preferred.

Using a five-layer carrier film 1 shown in FIG. 1 as an example, a carrier having a three-layer structure in which a polypropylene carrier film, a polyethylene carrier film, a polyethylene layer as an outermost layer, and a polypropylene layer as an inner layer are laminated below. Using the films as comparative examples, items such as the peel load of the carrier film, application stability, and styrene transmittance were compared.

The peeling load between the carrier film and the resin compound was determined by the following method. A resin compound is applied to a predetermined carrier film with a width of 500 mm and a thickness of 2 mm.
mm, and allowed to stand at 40 ° C. for 24 hours. Then, the material temperature was returned to 25 ° C.
Peeling was performed at an angle of 30 degrees at m / sec, and the load was measured with a digital push-pull gauge.

The stability of the resin compound applied to the carrier film during the production of the SMC was checked by visually checking the applied SMC sheet for wrinkles and breakage of the film. The styrene permeability of the carrier film is as follows.
m, applied under the condition of thickness 2 mm, left at 40 ° C. for 24 hours, returned the material temperature to 25 ° C., measured the weight, and left for 1 hour in an environment at a temperature of 25 ° C. and a relative humidity of 60%.
The weight was measured and the ratio of weight loss was defined as the styrene transmittance.

The results of the above measurements are shown in Table 1.

[0021]

[Table 1]

As shown in Table 1, the comparative example having no polyamide layer has a high styrene transmittance even in a carrier film having a thickness four times as large as that of the example, and scatters styrene in a working environment, Poor quality stability.
However, the carrier film of the present invention is excellent in peeling load, coating stability, styrene transmittance, and also in cost.

[0023]

As described above, the SM according to the present invention is used.
The carrier film for C is composed of a multilayer composite film of at least three or more layers obtained by laminating each layer of polypropylene, polyethylene, and polyamide.
It is configured to be adjusted to 0 to 100 microns, and further, because the polyethylene layer is located at the outermost layer and is in contact with the resin compound, good peelability of the polyethylene layer is obtained, and the This has the effect of improving the workability of separating the carrier film and the resin compound.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an embodiment of an SMC carrier film according to the present invention.

[Explanation of symbols]

 1 5 layer carrier film 2 polyethylene layer 3 polypropylene layer 4 polyamide layer

Claims (3)

[Claims] 1. A carrier film for SMC, which is tightly laminated on upper and lower surfaces so as to sandwich the upper and lower surfaces of a resin compound at the time of SMC production, wherein the carrier film is at least three layers obtained by laminating layers of polypropylene, polyethylene, and polyamide. A carrier film for SMC, comprising the above multilayer composite film. 2. The SMC carrier film according to claim 1, wherein the carrier film has a polyethylene layer provided on a contact surface with the resin compound. 3. The S according to claim 1, wherein the film has a thickness of 20 to 100 μm.
Carrier film for MC.