JP6662588B2 - Method for manufacturing FRP sheet - Google Patents

Description

  The present invention is an improvement in the method for producing an FRP sheet, in particular, a sheet-like molded product in a softened state can be formed into a predetermined thickness by sandwiching the same between rolling rolls, and furthermore, it suppresses the roughening of the sheet surface that occurs when the roll passes through the roll. The present invention relates to a method for producing an FRP sheet capable of improving the surface smoothness of the sheet.

  In recent years, in many fields, the use of FRP sheets having better strength and corrosion resistance than resin sheets has been progressing, and FRP sheets are well known as high-performance sheet materials. In the production of the FRP sheet, it is general that a reinforcing fiber (glass fiber, carbon fiber, or the like) oriented in the surface direction of the sheet is impregnated with a matrix resin and formed into a sheet.

  In particular, when the above-mentioned FRP sheet is formed, the thickness of the softened sheet-like molded product is adjusted by sandwiching it between rolling rolls (see Patent Documents 1 and 2). However, since the surface of the sheet-like molded product after passing through the rolling roller is roughened, there is a problem that the surface smoothness of the FRP sheet is impaired.

  Incidentally, as a cause of impairing the surface smoothness, as shown in FIG. 2, the contact state between a metal rolling roller (reference numeral M) and a sheet-like molded product (reference numeral S) is a line contact. It is presumed that one of the factors is that the orientation of the reinforcing fibers is disturbed when the sheet-like molded product is sandwiched in the above, and the disturbed reinforcing fibers roughen the sheet surface immediately after passing through the rolling roller.

  Conventionally, a technique for simultaneously adjusting the thickness of a sheet and cooling the sheet by sandwiching a soft sheet-like molded product with a metal endless belt has been known (see Patent Document 3). In the technology, the endless belt must be installed in a state of being tensioned to the pulley with a high tension, so that there is a disadvantage that the device structure is complicated and the device cost is increased.

JP-A-5-309679 JP-A-8-230055 JP-A-11-207778

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to sandwich a soft sheet-like molded product between rolling rolls and form it into a predetermined thickness, and furthermore, to complicate the device structure. An object of the present invention is to provide a method for producing an FRP sheet that can suppress the roughness of the sheet surface that occurs when the sheet passes through a rolling roll and improve the surface smoothness of the sheet.

  Means adopted by the present inventor to solve the above problem will be described below with reference to the accompanying drawings.

That is, the present invention relates to a method of manufacturing an FRP sheet, in which a FRP sheet extruded from a die of an extruder is formed into a predetermined thickness by a rolling roller while a matrix resin is in a softened state.
For the rolling roller, a pair of rubber rollers whose surface portions are formed of an elastomer material are used, and these rubber rollers are arranged so that a gap between the rollers is smaller than a sheet thickness after rolling, and the die is disposed from the die. The feature is that the extruded FRP sheet is passed through the gap between these rubber rollers while elastically deforming the roller surface.

  In the present invention, by arranging the pair of rubber rollers such that the gap between the rollers is smaller than the sheet thickness after rolling, it is possible to manufacture an FRP sheet having more excellent surface smoothness.

  Further, as for the rubber roller used for the above-mentioned rolling roll, it is preferable to use a rubber roller having a rubber hardness (Hs) of 50 to 90 ° so as to be able to strongly press the reinforcing fibers protruding to the sheet surface side.

  In addition, it is preferable to use a rubber roller having a surface roughness Ra (arithmetic average roughness) of 6.3 or less so that the surface of the sheet on which the surface shape of the roller is transferred becomes smoother.

  In the present invention, it is preferable to use discontinuous fibers as the reinforcing fibers of the FRP sheet so that the effect of improving the surface smoothness by the rubber roller can be obtained.

  In the present invention, in order to achieve both the strength and the surface smoothness of the FRP sheet, it is preferable that the compounding amount of the reinforcing fibers contained in the sheet is 20 to 50% by weight.

  In the present invention, since the rolling roller is made of an elastomer, the contact portion of the rolling roller can be deformed and brought into surface contact with the sheet-shaped molded product. Not only can be suppressed, but also in the case where the reinforcing fibers are slightly disturbed, the disturbed reinforcing fibers can be pressed down so as not to jump out to the sheet surface. Therefore, the surface shape of the rolling roller can be transferred to the surface of the sheet-shaped molded product, and the surface can be finished smoothly.

  Further, in the present invention, since it is only necessary to replace the rolling roller of the conventional apparatus with one made of an elastomer, there is no problem that the structure of the apparatus is complicated, and there is no fear that the apparatus cost increases. As described above, according to the present invention, the problem of the surface smoothness of the FRP sheet, which has been a problem in production, can be improved without excessive cost, and therefore, the practical utility value of the present invention is extremely high.

It is explanatory drawing showing the manufacturing method of the FRP sheet in this invention. It is explanatory drawing showing the manufacturing method of the conventional FRP sheet.

  Next, specific embodiments and preferable conditions for carrying out the present invention will be described.

[FRP sheet manufacturing method]
The method for producing the FRP sheet of the present invention will be described below with reference to FIG. First, as shown in FIG. 1, a thermoplastic resin is used as a matrix resin, and an FRP sheet S containing reinforcing fibers in the matrix resin is extruded into a sheet shape from a die of an extruder. Thereafter, the FRP sheet S is formed into a predetermined thickness through the gap between the pair of rolling rolls R while keeping the softened state.

  In addition, as for the above-mentioned rolling rollers RR, a pair of rubber rollers whose surface portions are formed of an elastomer material are used, and these rubber rollers are arranged such that a gap between the rollers is smaller than a sheet thickness after rolling. . Then, the FRP sheet S in a softened state is passed through the gap between these rubber rollers while elastically deforming the roller surface.

[Conditions of rubber roller used for rolling roller]
[1] Material and Thickness of Surface Layer As the elastomer material forming the surface of the rubber roller, silicone rubber can be preferably used, but natural rubber, synthetic rubber, and other thermoplastic elastomers can also be used. Further, the thickness of the rubber roller surface layer formed of the elastomer material can be freely designed within a range larger than the elastic deformation amount when passing through the FRP sheet.

[2] Surface Hardness The rubber hardness of the rubber roller is preferably in the range of 50 to 90 ° (more preferably 60 to 80 °). This is because if the surface hardness is less than 50 °, the roller surface is too soft and it becomes difficult to press the reinforcing fibers that have protruded to the sheet surface side, and if the surface hardness is more than 90 °, the rubber roller becomes difficult to deform.

[3] Surface Roughness The surface roughness of the rubber roller is preferably Ra 6.3 or less (more preferably Ra 1.6 or less). This is because if the surface roughness of the rubber roller is larger than Ra6.3, the surface of the sheet onto which the surface shape of the roller has been transferred becomes rough, and the sheet surface cannot be finished smoothly.

[4] Size of the gap between the rollers The size of the gap provided between the rubber rollers is preferably smaller than the sheet thickness after molding in order to elastically deform the roller surface. If it is too long, the softened resin accumulates on the roller, and the density and orientation of the reinforcing fibers are lost, which causes a deterioration in the smoothness of the sheet surface. Therefore, it is appropriately adjusted according to the characteristics of the matrix resin.

[Conditions of matrix resin used for FRP sheet]
The material of the matrix resin used for the FRP sheet S may be a thermoplastic resin, and may be selected from a polycarbonate resin, a polyethylene resin, a polypropylene resin, a vinyl chloride resin, an acrylic resin, and the like. However, it is necessary to consider the heat resistance and the like of the rubber roller according to the molding temperature of the resin used.

[Conditions of reinforcing fiber used for FRP sheet]
As the reinforcing fibers of the FRP sheet, discontinuous fibers (long fibers, short fibers, chopped strands, etc.) or continuous fibers can be used. In addition, since the discontinuous fiber has a greater adverse effect on the smoothness of the sheet surface due to the collapse of the orientation when passing between the rollers, the effect of improving the smoothness of the sheet surface by employing the manufacturing method of the present invention. Becomes larger. The amount of the reinforcing fibers is preferably 20 to 50% by weight based on the FRP sheet in order to achieve both strength and surface smoothness of the FRP sheet.

[Surface roughness of FRP sheet]
Regarding the FRP sheet molded to a predetermined thickness by rolling using the rubber roll, the surface roughness after molding is set to Ra 6.3 or less (preferably, Ra 3.2 or less), so that the reinforcing fiber It can be used in a wide range of fields as an FRP sheet having little disturbance of orientation in the sheet thickness direction and excellent surface smoothness.

[Effect verification test]
Next, a verification test of the effect of the present invention will be described below. First, in this test, molding was performed using a rubber roller whose surface portion was made of silicone rubber, the rubber hardness was 70 °, and the surface roughness of the roller was Ra 1.6. Further, a polycarbonate resin was used as a matrix resin of the FRP sheet, and a discontinuous fiber glass fiber was used as a reinforcing fiber. As a result, an FRP sheet excellent in surface smoothness having a surface roughness of Ra1.2 on the front side and a surface roughness of Ra2.2 to 2.5 on the back side was obtained.

R Rolling roller S FRP sheet

Claims (2)

An FRP sheet extruded from a die of an extruder, a FRP sheet having discontinuous fibers as reinforcing fibers, and a method of manufacturing an FRP sheet in which a matrix resin is formed to a predetermined thickness by a rolling roller while the matrix resin is in a softened state.
The rolling roller, using a pair of rubber rollers whose surface portions are formed of an elastomeric material, a pair of rubber rollers having a rubber hardness in the range of Hs60 to Hs80, and using the same rubber hardness, The pair of rubber rollers are arranged so that the gap between the rollers is smaller than the sheet thickness after rolling, and the FRP sheet extruded from the die is elastically deformed on the roller surface into the gap between these rubber rollers. A method for producing an FRP sheet, characterized by passing the sheet. The method for producing an FRP sheet according to claim 1, wherein the FRP sheet contains 20 to 50 wt% of reinforcing fibers.