JPH01136719A - Molding process of plastic planar body - Google Patents

Abstract

PURPOSE:To produce the molded object without uneven wall-thickness, while the uniform elongation of a plastic boardlike body in pressure molding is obtained by providing a notch or a hole in a specified part of the plastic boardlike body to be pressure-molded. CONSTITUTION:A notch 2 or a hole 3 is provided in the joint part between the clamp-part of a plastic boardlike body 1 and a mold. By providing this notch 2 or hole 3, a male mold or a female mold is press contacted with the plastic boardlike body 1, and when the tensile strength of the plastic boardlike body 1 begins to increase, the joint part is first elongated, and then the notch 2 or the hole 3 is deformed (e.g., a linear notch 2 is deformed into an almost triangular hole 2a). The portion in the mold of the plastic boardlike body 1 is not almost elongated. The elongation of the joint part is more increased than that of a conventional process, and the elongation of the portion in the mold is more decreased than that of the conventional process. Accordingly, the width of the joint part may be more narrowed than that of the conventional process, whereby its yield is improved, and the uniform thickness of a product is obtained, while the thickness of the portion being in the mold and becoming the product, is increased.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention relates to single or laminate synthetic resin sheets that are plastic at high or low temperatures, and the use of the above-mentioned plastic synthetic resin sheets and fibers such as woven, knitted or non-woven fabrics. The present invention relates to a forming method for forming a multi-curved surface by stretching, deep drawing, etc., a plastic plate-like body such as a sheet, a carpet, or a laminate with a needle carpet.

(Prior art) A thermoplastic synthetic resin sheet or other plastic plate-like body is pressed into contact with a male mold or a female mold using a vacuum or compressed air, or by using both the male mold and the female mold. When molding a compound curved surface corresponding to the shape of a male mold or a female mold, conventionally, the periphery of the plate-shaped body was fixed with a large number of clamps. It should be noted that there is a known method in which the above-mentioned clamp is provided so as to be able to slide horizontally and up and down and is pulled by a spring, so that when the above-mentioned plate-like body stretches a lot, the above-mentioned clamp slides against the tension of the spring. It is being

(Problem to be Solved by the Invention) When a fixed clamp is used, the inner part of the mold stretches more than the connecting part between the fixed clamp of the plastic plate and the mold, and the connecting part Since the elongation is small, almost the entire area of the connecting part and clamp part (grasping allowance) is discarded, resulting in a low yield.

In particular, all of the above-mentioned fixed clamps are arranged in one plane, so when the outer peripheral edge of the mold is located above or below compared to the arrangement plane of the clamps, the above-mentioned connecting part There was a problem that the yield was further reduced due to the slope.

Additionally, if the clamp is tensioned by a spring, the clamp will slide due to the tension of the plastic plate, so the yield will increase somewhat compared to a fixed clamp.
Since the sliding direction is limited, the elongation of the connecting portion is smaller than that of the inner portion of the mold, as in the case of the fixed clamp, and the increase in yield was extremely small.

Moreover, it is extremely troublesome to change the elasticity and arrangement density of the springs depending on the shape of the mold, or to replace springs whose elasticity has changed due to fatigue.

The present invention provides a molding method in which only the connecting portion between the clamp portion and the inner portion of the mold to be manufactured can be expanded, thereby improving the yield.

(Means for Solving the Problems) As shown in FIG. 1, in a method for molding a thermoplastic plate-like body in which a plastic plate-like body 1 is pressed against a male mold or a female mold and shaped by any means, A large number of short cuts 2 or holes are intermittently provided along at least the inner side of the clamp portion of the periphery of the peripheral edge and the unnecessary portion of the center of the plastic plate-like body 1.

The above-mentioned plastic plate-like body may be a single thermoplastic synthetic resin sheet such as polyethylene, polyvinyl chloride, polypropylene, etc. or a laminate of two or more types of thermoplastic synthetic resin sheets, or may be a laminate of two or more thermoplastic synthetic resin sheets. It may be a single unit or a laminate in which fiber sheets such as pile carpets, needle carpets, nonwoven fabrics, and single-knit woven fabrics made of synthetic fibers such as nylon, polyester, and polypropylene are laminated.

The cuts 2 provided in the above-mentioned plastic plate-like material 1 are the short straight ones shown in Fig. 1, and the ones with small circular holes made at both ends of the short straight lines to prevent tearing, as shown in Fig. 2 (,). as shown in Figure 4(a), one with small circular holes at both ends of an inverted V-shape, one with small circular holes on both ends of a waveform as shown in Figure 8(a), As shown in Figure 9(a), it may be an inverted U-shape with small circular holes at both ends.

Further, the circular holes at both ends may be omitted from the inverted V-shape shown in FIG. 4(a), the waveform shown in FIG. 8(a), the inverted U-shape shown in FIG. 9(a), etc. In addition, the above cut 2 is shown in Fig. 1,
Figures 2(a), 4(a), 8(a) and 9
They may be arranged in one line as shown in Figure (a), or in Figure 3 (
a), a staggered arrangement as shown in FIGS. 5(a) and 7(a), or a mixture of two or more types of cuts 2 with different shapes as shown in FIG. 6(a). May be arranged.

Further, the holes 3 in the synthetic resin plate-like body 1 are the 10th holes.
They may be circular as shown in the figure, slot-shaped as shown in FIG. 11, diamond-shaped as shown in FIG. 12, etc., and these may be arranged in one row, multiple rows, or staggered. Further, they can be arranged in a mixture with the cuts 2 or holes 3 of different shapes shown in FIGS. 2(a) to 9(a).

(Function) The connecting part between the clamp part and the mold of the plastic plate-like body 1 becomes easier to stretch than other parts due to the presence of the cuts 2 or holes 3, so that the plastic plate-like body 1 has a male or female mold. When the tension of the above-mentioned plastic plate-like body 1 starts to increase after being pressed,
The above-mentioned joint stretches first and the cut 2 or hole 3 is deformed, for example, the short straight cut 2 in FIG. 1 is transformed into an approximately triangular hole 2a, and in FIGS. ) The cuts in the figure are transformed into the holes in the figure (b), respectively,
In addition, the portions where the tension is large are greatly deformed, and the portions inside the mold of the plastic plate-like body 1 hardly elongate.

Then, as the molding progresses, the plastic plate-like body 1 is strongly pressed against the periphery of the mold, and after the plastic plate-like body 1 no longer slips at the periphery, it is stretched.

Therefore, the elongation of the connecting portion is increased compared to the conventional method, and the elongation of the inner part of the mold is decreased compared to the conventional method.

Note that by arranging the cuts 2 or holes 3 more densely than in other parts at the connecting parts on both sides of the part where the elongation of the inner part of the mold becomes large due to the shape of the mold, the elongation of the inner part of the mold can be made uniform. Furthermore, the elongation of the joint portion varies depending on the shape of the cut 2 and hole 3.

For example, the inverted V-shaped cuts 2 in Figure 4 make it easier to stretch the joint than the short linear cuts 2 in Figures 1 and 2, so the same-shaped cuts 2 or holes 3 are arranged closely. Instead, it is possible to provide a cut 2 or a hole 3 with a shape that makes it easier to stretch the connecting part, and especially for areas where the expansion inside the mold is large, it is possible to provide a shape that makes the connecting part easier to stretch, such as an inverted V-shape. The cuts 2 or holes 3 can be arranged closely. In addition, when one plastic plate-like body 1 is divided into two or more areas and the two or more areas are simultaneously molded using two or more molds arranged in parallel, the two or more areas are molded along the boundary line of the two or more areas. By providing the above-mentioned cuts 2 or holes 3, the elongation of two or more parts inside the mold can be made uniform. In addition, even in the inside of the mold of the plastic plate-like body 1, unnecessary parts that are removed by drilling or the like after molding are completed.

By providing the above-mentioned cuts 2 or holes 3, or cross-shaped cuts 4 as shown in FIG. The elongation of the part that becomes the product can be suppressed to a low level.

(Example) A rectangular plastic plate-like body 1 was formed into the shape of a gutter as shown in FIG.

The plastic plate-like body 1 has a width of 1550 ms and is made of a nylon nonwoven fabric and a polyethylene sheet back coat.
Using a field with a length of 2115 m and a thickness of 8, have a clamp part of 20 mm width on two opposing sides, and a clamp part of 10 mm width on the inside.
The joint portion of Im was removed, and one row of short straight cuts 2 as shown in FIG. 1 were provided in this joint portion. Then, straight lines were drawn vertically and horizontally at Looms intervals on the entire surface of the plastic plate-like body 1, and the elongation was determined by measuring the intervals between the straight lines at each part after molding. However, the molding was carried out using a male mold and a female mold, and the height of the left and right edges 10a of the obtained product 10 was 100 nm, the width of the left and right bottoms 10b was 450 nm, and the height of the central slope 10c was 120 nm. , the width of the central mountain portion 10d was 2001 m. Example 1 in which the lengths of the linear cuts 2 are varied in the above clothing
~3. And the elongation (%) after molding of each part obtained for Comparative Example 1 without cut 2 is shown.

As is clear from the clothes above, if you change only the length without changing the interval between the cuts 2, the longer the cuts 2.

The elongation within the mold is reduced, and the elongation (%) when the length of the cut 2 is set to 2001 is significantly reduced to 58% of the elongation (%) of the comparative example in which the cut 2 is not provided.

Next, a plastic plate-like body 1 in which a needle carpet made of polyester fiber was laminated on the upper surface of a thermoplastic synthetic resin sheet made of polyvinyl chloride was prepared, and an automobile interior mat 11 shown in FIG. 15 was formed.

In the figure, a connecting part 11b is shown at the upper right of the floor part 11a, and a clamping part 11c is shown at the upper right of the connecting part 11b.
In the center, there is a protrusion lid in the length direction and a protrusion 11 in the width direction.
e is formed in a cross shape. The width of the spherical portion 11a, ie, the mold width, was 1200 mm. Further, the length between both ends 8.8 of the spherical portion 11a measured along the two-dot chain line P passing through the upper surface of the intersection of the convex lid and lie after molding was 1420 ma+. In this case, Comparative Example 2 does not provide the cut 2 or hole 3 in the connecting portion 11b, and the inverted V-shaped cut 2 (length Q = 5
5m, width at both ends b = 10m, distance between adjacent cuts 2 m
When comparing the width t (pus) of the connecting portion 11b necessary for molding with respect to Example 4 in which a
The width t of Embodiment 4 was 110I, while the width t of Embodiment 4 was 110I.
1I1, which was reduced to about 9% of the comparative example. Therefore, the width of the original fabric (L+2t) excluding the clamp part 11c is 1420 mm in Comparative Example 4, and 1220 nys in Example 4.
, about 86% of Comparative Example 4, and in Example 4, the plastic plate-like body 1 is reduced by about 14% compared to Comparative Example 2, and the spherical portion 11a and the protruding strip 11d are used as products.

The thickness of the lie increases, the defects such as the penetration of the ground are eliminated, and the quality improves.

(Effects of the Invention) This invention provides cuts or holes of arbitrary shape in the joint between the clamp part where the plastic plate-like body is clamped during molding and the inner part of the mold that is molded into a product. Because of this, the elongation of this connecting part increases more than before, and the elongation of the part inside the mold decreases more than before. Therefore, the connecting part can be made narrower than before, improving the yield, increasing the thickness of the inside of the mold that becomes the product, and eliminating the problem of see-through, especially when the surface layer of the plastic plate is carpet. quality is improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating an embodiment of the present invention, (a) of FIGS. 2 to 9 are plan views of cuts having different shapes or arrangements, and (b) are views caused by deformation of the above-mentioned cuts. 10 to 12 are plan views of holes with different shapes, FIG. 13 is a plan view of cross-shaped cuts, and FIG. 14 is a plan view of the trough-like bodies of Examples 1 to 3. cross section,
FIG. 15 is a perspective view of the automobile interior carpet of Example 4. 1: Plastic plate-like body, 2.14: Cut, 3: Hole. Patent applicant: Sugihara Sei No Kogyo Co., Ltd. Agent Patent attorney: Yoshi 1) Ryo Tsukasa Figure 5 Figure 8 Figure 9 Figure 10 Figure 11 Figure 14

Claims (1)

[Scope of Claims] [1] A method for molding a plastic plate-like body in which a plastic plate-like body is pressed against a male mold or a female mold by any means to shape the plastic plate-like body; A method for forming a plastic plate-like body, comprising the step of providing intermittently a large number of short cuts or holes along at least the inner side of the clamp portion at the periphery of the portion. [2] The method for molding a plastic plate-like body according to claim 1, wherein the plastic plate-like body is a laminate of a plastic synthetic resin sheet and a fiber carpet. [3] The method for molding a plastic plate-like body according to claim 1 or 2, wherein the cuts or holes are provided in a plurality of rows in a staggered arrangement. [4] The method for forming a plastic plate-like body according to any one of claims 1 to 3, wherein a mixture of cuts or holes having different shapes is provided. [5] The method for forming a plastic plate-like body according to any one of claims 1 to 4, wherein the cuts are formed in short straight lines substantially parallel to the periphery of the plastic plate-like body. [6] The method for forming a plastic plate-like body according to any one of claims 1 to 4, wherein the cut is formed in an inverted V-shape or an inverted U-shape substantially parallel to the periphery of the plastic plate-like body. . [7] The method for forming a plastic plate-like body according to claim 1 or 4, wherein the cuts are formed in a wave shape along a straight line substantially parallel to the periphery of the plastic plate-like body. [8] The method for molding a plastic plate-like body according to any one of claims 1 to 4, wherein the hole is a long hole parallel to the periphery of the plastic plate-like body.