JPS6189033A - Continuous manufacture of laminate - Google Patents

Abstract

PURPOSE:To produce a laminate at a practical speed using a practical hardening apparatus, by cutting a laminate in the course of the hardening into a practical and desired length, and allowing the hardening to take place after the cutting. CONSTITUTION:When a thermosetting resin is used, a guillotine cutter 7 positioned after a hardening furnace 7 cut periodically a laminate into a prescribed length, and the cut laminate 8 is placed on a belt conveyor 10 to be introduced into a second hardening furnace 8. The hardening conditions in the second hardening furnace are such that the temperature is higher and the period is shorter than in the first hardening furnace 5. Then the cut laminate on the belt conveyor is passed into a warp correcting apparatus 11 to produce a final product. The correction of warp is carried out, for example, by passing the laminate through three adjacent rolls longitudinally and then if required laterally.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for continuous molding of laminates.

Conventionally, laminates are made by impregnating a base material with a resin component dissolved in a solvent, then drying the solvent to create a prepreg.
This is manufactured by cutting it into a certain size, stacking them in multiple layers, and in some cases overlaying metal foil, and applying pressure and heat using the hatch method, but the process is complicated and it is a hatch production method. Therefore, the reality is that it requires a lot of manpower, and there is a big problem with productivity.

In recent years, from this viewpoint, several proposals have been made for continuously manufacturing laminates.

For example, U.S. Pat. No. 2,596,162 discloses that a continuous base material is impregnated with a resin liquid, wrapped with a cover sheet such as cellophane, and then cut after partially polymerizing the resin.
A method for manufacturing a fiber-reinforced resin product is described in which a cut base material is molded into a desired shape and finally polymerization of the molded base material is completed. In this method, in-line curing is stopped while the polymer is still partially cured, and after cutting, the partially polymerized resin-impregnated base material is placed on a flat table or fixed to a frame into the desired shape, such as a flat plate. This is carried out by completing the polymerization of the resin while maintaining it in the final desired shape. Therefore, this method has drawbacks such as a large number of steps that must be carried out off-line and difficulty in appropriately controlling the degree of polymerization.

On the other hand, JP-A No. 52-10390 describes a method for continuously manufacturing laminates, particularly fully bent foil-clad laminates, by a pultrusion method. The process is carried out continuously in-line from impregnation of the substrate until completion of curing of the laminate. However, in laminates manufactured by this method, especially laminates clad with metal foil on one side, residual strain occurs in the machine direction, and when used in the laminate processing process or incorporated into a set, this appears as warping, causing various inconveniences. There were drawbacks.

The present inventors conducted extensive research on a method for continuously manufacturing such a laminate, and as a result, they arrived at the present invention.

That is, in such a method, the impregnated base materials are usually laminated before the resin component impregnated into the base material is cured, and then the resin component is cured, but in general, the curable resin loses volume as it hardens. shrinks, causing residual strain inside the resin and warping or warping of the product. In addition, if the resin has not completely cured, if the product is subsequently placed in a heated environment, not only will new warpage and twisting occur, but incomplete curing may cause the heat resistance to deteriorate. Significantly reduces properties such as chemical resistance and mechanical properties.

According to the research conducted by the present inventors, in order to complete the curing when continuously manufacturing a laminate, an extremely long curing device or an extremely slow line speed is required, which is not desirable. However, the present inventors cut the resin during the curing process, and then, for example, stacked the pieces into a regular size body in multiple layers, and if the resin is thermosetting, the resin is cured in a heating chamber, etc. After cutting, a large amount of the laminate can be cured at the same time.

Therefore, continuous curing of the laminate can be achieved by, for example, (1) being able to be cut sufficiently with a guillotine cutter, and (2) in some cases, the coating that is laminated for the purpose of forming the surface layer of the laminate can be cured without any obstruction. Since it is sufficient to reach a state where it can be peeled off, we have discovered that it can be manufactured using a practical curing device and a practical line speed, and have arrived at the present invention.

In the present invention, a plurality of sheet-like base materials are continuously conveyed, impregnated with a curable resin liquid, etc., laminated with impregnated base materials, laminated with metal foil, and cured, etc., and the laminate is formed in the curing process. This is a continuous manufacturing method for a laminate, which is characterized by continuously cutting the laminate to a desired length suitable for practical dimensions, and further curing the product after cutting.

According to the present invention, for example, when using an unsaturated polyester resin that is liquid at room temperature without using a solvent, in order to proceed with sufficient curing with substantially no pressure, depending on the formulation,
Even if it takes 10 hours at 0° C., cutting is only possible in about 15 minutes, and therefore the present invention is advantageous.

Furthermore, in the case of continuously producing a single-sided metal foil clad laminate, the residual strain due to curing shrinkage of the resin layer can be relatively easily removed by releasing it as warp in the middle direction, which is particularly the case. Residual strain in the longitudinal direction, that is, the machine direction, cannot normally be removed because it is long, and therefore anisotropy occurs in the residual strain in the vertical and horizontal directions of the product. is undesirable as it causes increased warpage and twisting when the product is subsequently placed in a heated environment. In the present invention, since curing is further advanced after cutting, warpage and residual strain can be made substantially uniform in the process to a practically acceptable extent. However, the magnitude of warp in such a metal foil-clad laminate varies depending on the resin used, and is generally small for epoxy resins and large for unsaturated polyester resins and diallyl phthalate resins. Furthermore, even if the resin is of the same type, it varies depending on its composition. For example, a 35 μm thick copper foil laminate made of unsaturated polyester resin and paper has a thickness of 1.6 mm, and the amount of warpage specified in JIS C-6481 is 0.5 to 30% depending on the treatment of the resin components.
There is a range of degrees. Using a resin component with large warpage may be harmful depending on the purpose of use and is therefore undesirable. However, the present inventors have found that after cutting the above-mentioned continuous body, appropriate curing conditions are applied, for example, in the case of thermosetting resins, conditions higher than continuous curing conditions are desirable, or equivalent to heating conditions to which the product is exposed in practice. By proceeding with curing at a temperature of It has been discovered that the warpage that occurs is significantly reduced, and the present invention has been developed.

That is, the present invention is characterized in that the above steps are added to the continuous production of the laminate. Warp correction can be achieved, for example, by passing the roll between three adjacent rolls in two directions, vertically and horizontally, if necessary.

For example, when using a thermosetting resin, a guillotine cutter installed after the curing furnace periodically cuts the resin to a certain length in the longitudinal direction, and the cut laminate is carried on a belt conveyor for the second curing process. Enter the furnace. The curing conditions in the second curing furnace are preferably higher temperature and shorter time than those in the first curing furnace. Next, it rides on a belt conveyor and enters a warping correction device, where the final product is manufactured. By using the methods and equipment described above, it is possible to produce insulating laminates for electrical purposes, metal foil laminates, or decorative laminates with high productivity and excellent characteristics, such as those with a thickness of about 0.1 to 5 mm. The body can be manufactured continuously.

Examples Commercially available unsaturated polyester resins (Polymer 6311,
A resin solution containing 100 parts by weight of Takeda Pharmaceutical Co., Ltd., 1 part by weight of dropperoxide, and 0.2 parts of 5% cobalt naphthenate was mixed into a commercially available kraft paper (ZBS-135, Sumikokusaku Pulp) was continuously impregnated, six sheets were laminated, and at the same time a 35 μm thick electrolytic copper foil was laminated, and after being continuously cured in a curing oven at 110°C for 20 minutes, it was cut with a guillotine cutter. Further, post-curing was performed at 130° C. for 20 minutes in a box-shaped heating furnace to obtain a single-sided copper foil-clad laminate having a thickness of 1.61. This material was rewarped in both the vertical and horizontal directions using three rolls, and the changes in warpage due to heating were measured for the flattened product. The results are shown in Table 1.

Comparative example 4.
The first half of the curing oven is 110°C, and the second half is 130°C.
The laminate was impregnated and laminated under the same conditions as in the example, passed through a curing furnace at 1/2 the speed of the example, cured, and then cut with a guillotine cutter to form a single-sided copper foil with a thickness of 1.6 m. A stretched laminate was obtained.

Further, three rolls were used to correct the warpage in both the vertical and horizontal directions, and the changes in warpage due to heating were measured for the flattened product. The results are shown in Table 1.

Table 1 Examples 0 1.3 1.9 2.2
Comparative example 0 2.8 4.0 4.7
The dimensions of the laminate used for warp measurement are 330m + l x 250
1 m, and the heat treatment at 130° C. for 10 minutes was repeated three times, and the amount of warpage was measured each time. To measure the warpage, the laminate was placed on a surface plate, and the average value of the distances from the four corners from the surface plate was taken as the amount of warpage.

[Brief explanation of the drawing]

FIG. 1 is an explanatory schematic diagram showing an example of an apparatus for carrying out the method of the present invention. 1 is a sheet-like base material such as glass cloth or paper, 2 is a resin liquid impregnation device, 3 is a metal foil, 4 is a covering film such as cellophane, 5
1 is a curing device, 6 is a continuous laminate in the curing process, 7 is a cutting machine, 8 is a curing device, 9 is a cut laminate, 10 is a heltoconhair, 11 is a warp correction machine, 12 is a turntable, 13 is a It is a product.

Claims (2)

[Claims] (1) Impregnating multiple sheet-like substrates with a curable resin liquid while continuously conveying them, laminating the impregnated substrates, laminating the cover sheet or metal foil, and curing the laminate while continuously conveying them. In a method for continuous production of a laminate, the continuous curing during conveyance is temporarily discontinued before the curing of the resin is completed, at least when the laminate reaches a stage where it can be cut with a guillotine cutter, and the laminate is cut to a practical size. 1. A method for continuously manufacturing a laminate, which comprises cutting the cut laminate into a desired length, and then further curing the cut laminate until the curing is completed. (2) The method according to claim 1, wherein the curing temperature after cutting is higher than the continuous curing temperature.