JPH0148144B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a sheet for joining resin molded products that is used to join resin molded products made of a resin that is difficult to adhere to, such as FRP resin (glass fiber reinforced unsaturated polyester resin), and a resin using the same. This invention relates to a method for joining molded products. [Conventional technology] When large or long products such as water storage tanks, coastal water pipes, and drainage pipes are made of synthetic resin such as FRP resin, they cannot be molded all at once, so a split mold is used to mold multiple products. It is common practice to make separate resin molded products and join them together to form a single product. When performing this bonding, simply treating the surface of the split resin molded product with a primer or applying adhesive will not provide sufficient bonding strength, so in most cases, the surfaces of the split resin molded product that are to be joined are sandblasted or Alternatively, the surface may be roughened by sanding, and then bonded using an adhesive. [Problems to be solved by the invention] When joining in this way, dust is generated due to sanding of the surface of the split resin molded product, which deteriorates the working environment, and the generated dust adheres to the skin, causing serious problems. It causes serious hygienic problems such as itching, getting into the ears, causing hearing loss (combined with the noise generated), and causing respiratory problems. If the surface is roughened by heating, it has the drawback that it is extremely unstable and uneven, and high bonding strength cannot be obtained. Furthermore, even if a completely rough surface is formed by sanding or the like, there is a problem in that sufficient bonding strength is not obtained. For this reason, there is a strong demand for the development of a new method to replace such sanding. The present invention was made in view of the above circumstances, and an object thereof is to provide a sheet for joining resin molded products and a method for joining resin molded products, which can easily and firmly join even large resin molded products. [Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for curing a resin molded product after completing curing with the surface of the resin molded product being pressed against the surface of the resin molded product before curing. A sheet for joining resin molded products that peels off from the surface of the resin molded product to form a rough surface of the resin molded product,
A resin molded product in which a base material is a woven fabric made of twisted yarns mainly consisting of short fibers, and a sheet-like elastic body is provided with the woven fabric embedded to a predetermined thickness on the back side of this base material. The first point is the sheet for joining resin molded products, and the surface side of this sheet for joining resin molded products is pressed against the surface of the resin molded product before curing to complete the curing of the resin molded product, and then the sheet for joining resin molded products The sheet is peeled off from the surface of the resin molded product, and the surface of the resin molded product is processed into a rough surface where some of the resin in the resin molded product is raised in the form of threads, and this rough surface is used to join the resin molded products. This is the second point. [Function] That is, the present invention does not roughen the surface of a resin molded product by polishing it prior to bonding as in the past, but instead roughens the surface of the resin molded product during or after molding in an uncured state. A special sheet for joining resin molded products such as the one described above is pasted on the surface of the molded product by pressing the woven fabric side of the surface, and after the molded product has hardened, the sheet for joining resin molded products is applied from the surface. After peeling off, an uneven surface is formed on the surface of the resin molded product by transferring the unevenness of the texture of the woven fabric of the (A) resin molded product bonding sheet. (B) A part of the resin molded product is raised from the surface of the molded product as resin fluff by twisting the woven fabric. (C) A part of the twisted yarn of the woven fabric of the sheet for joining resin molded products is transferred to the surface of the resin molded product and planted. This allows the surface of the molded product to have a rough surface with a very special structure. Therefore, by applying adhesive or the same type of resin as the resin molded product to this rough surface, stacking it on the rough surface of another similarly obtained molded product and applying pressure, an extremely strong bond can be created. will be obtained. Next, the present invention will be explained in detail. FIG. 1 is a configuration diagram of an example of a sheet for joining resin molded products of the present invention, in which 1 is a base material made of a woven fabric whose warp and weft are composed of twisted yarns mainly consisting of short fibers, and 2 is a The raised surface of the woven fabric 3 is a sheet-like elastic body that lines the woven fabric 1. The constituent fibers of the woven fabric 1 serving as the base material are as follows:
Commonly used fibers include Tetron, nylon, vinylon, glass fiber, etc.
They are formed into short fibers or long fibers, and are constructed into twisted yarns made of short fibers alone or mixed fibers of short fibers and long fibers, and used alone or in combination. Therefore, in the present invention, "mainly short fibers" means short fibers alone, mixed fibers of short fibers and long fibers, or a combination of both. In view of the condition of the rough surface, it is preferable to use a woven fabric using twisted yarn made of only short fibers as the woven fabric 1 of the sheet for joining resin molded products.
However, from the viewpoint of the peelability of the sheet for joining resin molded products from the resin molded product (considering the work involved, the sheet for joining resin molded products will not be damaged even if it is peeled off with strong peeling force), it is difficult to separate short fibers from long fibers. Woven fabrics using twisted yarns made of mixed fibers (high strength) or woven fabrics that combine twisted yarns made of mixed fibers of short fibers and long fibers and twisted yarns made of short fibers alone can be used as sheets for joining resin molded products. preferable. Short fibers refer to fibers whose length is about 3 times the fiber diameter to about 100 mm. Of the woven fabrics used for the bonding sheet, the most preferable fabric is a plain weave made by twisting 30 short fibers each having a thickness of 2 denier and a length of 50 mm. The sheet-like elastic body 3 is made of natural material. It is made of synthetic rubber, synthetic resin, etc. and has the ability to form sheets. and,
It is provided by topping, laminating, brushing, etc. on the surface of the woven fabric 1. Roughening of the surface of a resin molded product using such a sheet for joining resin molded products is performed, for example, as follows. That is, when the resin molded product is not yet cured, the sheet for joining the resin molded product is pasted by pressing its woven fabric side against the surface of the resin molded product. Due to this pasting, a part of the resin on the surface of the resin molded product flows, moves as a flow along the unevenness of the weave of the woven fabric of the sheet for joining resin molded products, and penetrates into the interior through the weave. . As another trend,
It moves by capillary action along the twists of the twisted yarns that make up the woven fabric of the sheet for joining resin molded products, and penetrates into the twists. Since the sheet for joining resin molded products of the present invention has a sheet-like elastic body 3 on the back side, the presence of the elastic body 3 prevents the resin from penetrating into the weave of the woven fabric of the sheet for joining resin molded products. It penetrates to the part where it touches the fabric and is stopped there, preventing it from reaching the back of the fabric or the opposite side. In addition, the resin that enters along the twists of the twisted yarns of the woven fabric due to capillary phenomenon is caused by the fact that the woven fabric of the sheet for joining resin molded products of this invention is mainly composed of short fibers, and the twisted yarns are intermittent. Since it is in a state where the intrusion is blocked at the interrupted part, it becomes a short thread-like state. In this manner, curing of the resin molded product is completed with the sheet for joining the resin molded product attached. In FIG. 2, 1 is a woven fabric, 2 is a raised cloth, 3 is a sheet-like elastic body, and 4 is a resin molded product. When the resin molded product joining sheet 5 is peeled off after the resin molded product 4 has hardened, (A) an uneven surface formed along the surface irregularities of the woven fabric of the resin molded product joining sheet, and (B) (C) The resin formed by penetrating by capillary action along the twists of the twisted yarns constituting the woven fabric of the sheet for bonding resin molded products is pulled out and stands up in a raised shape on the surface of the resin molded product. The short fiber threads of the twisted yarn constituting the woven fabric of the sheet for joining resin molded products are transferred to the surface of the resin molded product, forming a flocked shape, so that the surface of the resin molded product has an uneven surface (above A). ), and from the uneven surface, the threads made of the resin of the resin molded product (B) and the threads made of the short fiber yarn of the woven fabric constituting the sheet for joining resin molded products (C).
It is densely brushed and has an extremely fine rough surface. This is shown in FIG. In Fig. 3, 6 is a convex portion formed by the woven fabric (the part that penetrates into the plain weave) of the sheet for joining resin molded products, and 7 is the overlap between the warp-twisted yarn and the weft-twisted yarn of the woven fabric 1. This is a recess formed by the part pressed by the ivy part. These convex portions 6 and concave portions 7 make the surface of the resin molded product uneven. 8 is a thread-like body made of resin of the resin molded article, and 9 is a nap made of short fibers transferred from the surface of the woven fabric 1. In this case, the peeling of the sheet for joining the resin molded product from the surface of the resin molded product is prevented because the back surface is lined with a sheet-like elastic material and the intrusion of the constituent resins of the resin molded product is suppressed at that part, as described above. Because of this, it can be easily peeled off. In particular, considering releasability, narrow tape-like sheets (50 mm width,
It is preferable to have a width of 100 mm). To join the molded products formed in this way, for example, a resin of the same type as the resin of the resin molded product is applied to the rough surface, and the resin is pressed against the rough surface of the resin molded product obtained in the same manner. This can be done by curing. In this case, the resin molded products are joined by the action of the rough surface which is an uneven surface, the action of the resin filaments standing up from the rough surface, and the action of the threads transferred from the woven fabric. Because the properties are significantly improved, the bond is extremely strong (bonding force is strong enough to cause fracture of the base material). If a woven fabric using a twisted yarn consisting of only long fibers is used instead of a twisted yarn consisting mainly of short fibers, the length of the twisted yarn consisting of long fibers becomes longer, so that the resin that enters by capillary action is It penetrates deep into the body and becomes long thread-like.
When peeling off the sheet for joining resin molded products, the twisted yarn cannot be pulled out from the twists, making it impossible to peel off. If this is forcibly peeled off using a machine, the filament will be cut off from the root, and no raised resin will remain on the surface of the resin molded product. Therefore, even if a woven fabric using a twisted yarn consisting of only long fibers is used, the same effect as the sheet for joining resin molded products of the present invention is not observed. In addition, how to use the sheet for joining resin molded products is as follows.
In addition to the above-mentioned method of pressing a resin molded product bonding sheet onto the surface of an uncured resin molded product, for example, it is possible to
Glue the sheet for joining resin molded products with the sheet-like elastic body on the back side facing the joining mold,
Resin molding may be performed in this state to produce a resin molded product, and then the sheet for joining the resin molded product may be peeled from the obtained resin molded product (curing agent). In this way, when the sheet for joining resin molded products is used by being attached to a mold, it can be used as a sheet-like elastic body on the back side of the sheet for joining resin molded products, and it can be attached to the mold with its own adhesive force. It is preferable to use a material that can be used. An example of such a sealant is a urethane sealant (Millionate NS-12, manufactured by Hodogaya Chemical Co., Ltd.). Furthermore, when molding a long object such as a ship's hull, a molding resin (containing glass fiber) is laminated on the mold to a specified thickness, and then a tape is formed on top of the molding resin (containing glass fiber). The sheets for joining resin molded products are placed in a row with their surfaces aligned with the resin surface to cure the resin, and then the tape-shaped sheets for joining resin molded products are sequentially peeled off to form a rough surface. Molding can be easily carried out by repeating the process of laminating a new layer on the rough surface and placing a resin molded product bonding sheet on top of it. Next, examples will be described together with comparative examples. [Example] Vinylon short fibers with a fiber length of 51 mm and a thickness of 2 denier
35% and 65% Tetoron short fibers with a fiber length of 51 mm and a thickness of 2 denier are twisted to create a twisted yarn consisting of short fibers alone, and this is used to create a plain weave woven fabric (warp; the above twisted yarn 30%).
Main bundle, weft; make a bundle of 30 twisted yarns x 2), apply a urethane sealant (Millionate NS-12, manufactured by Hodogaya Chemical Co., Ltd.) to the back side, and let it penetrate up to half the thickness of the woven fabric to make the resin. A sheet for joining molded products was obtained. Next, this sheet for joining resin molded products is attached to the part of the mold surface corresponding to the surface of the plastic molded product to be joined, with the urethane sealing material on the back side facing the mold surface. In this state, a molding resin consisting of a mixture of commercially available polyester resin and glass fiber was laminated on the mold surface and cured. Then, the resin molded product joining sheet was peeled off from the obtained plastic molded product. Next, an unsaturated polyester resin is applied to the rough surface of this material, and the rough surface of a similarly obtained plastic molded product is laminated and pressed against the rough surface, and the unsaturated polyester resin is cured to form two plastic molded products. were joined. [Comparative Example] Two plastic molded products were made without attaching the resin molded product bonding sheet to the mold. Next, the rough surfaces of these molded products were sanded, and an unsaturated polyester resin was applied and bonded. The strength of the joints of the joined products obtained in the above Examples and Comparative Examples was measured. The results are shown in the table below, and it can be seen that the examples are significantly superior.

[Table] Head speed 5mm/〓 Overlapping joint length 12.5mm
[Effects of the invention] The sheet for joining resin molded products of the present invention
−It is not just a canvas as disclosed in Publication No. 56059, but a special one in which a sheet-like elastic body is partially embedded in the back side of a woven fabric made of twisted yarn mainly consisting of short fibers. It is. Therefore, when it is pressed onto the surface of an uncured resin molded product and roughened, the surface of the resin molded product will not only have the irregularities of the weave of the woven fabric on the surface of the sheet for joining resin molded products, but also
The resin of the resin molded product seeps into the twists of the woven fabric on the surface of the sheet for joining resin molded products and hardens, and then the raised material is pulled out by peeling off the sheet for joining resin molded products, and the woven fabric The short fibers constituting the twisted yarn migrate to form an uneven, rough surface in which countless flocked materials are planted. Therefore, using this, resin molded products can be easily joined. Furthermore, since the joining method of the present invention uses the sheet for joining resin molded products and joins the resin molded products in the manner described above, there is no need for the conventional joining process, and resin molding can be performed extremely easily. Can join products. Moreover, according to this method, the sheet for joining resin molded products can be used repeatedly, which is highly economical. Further, according to the present invention, the strength of the joint portion is extremely high, so that it can be applied to joining parts where a large force is applied to the joint portion. Moreover, it can be used for single-layer layer molding of long objects such as ship hulls by forming the sheet for joining resin molded products into a tape shape and placing it in rows on the uncured excipients on the mold. This makes it possible to perform one-layer multilayer molding of long objects extremely well, which has not been able to achieve good results in the past.

[Brief explanation of drawings]

FIG. 1 is a side view of the sheet for bonding resin molded products used in the present invention, FIG. 2 is an explanatory view of its use, and FIG. 3 is a partially enlarged perspective view of the rough surface. DESCRIPTION OF SYMBOLS 1... Woven fabric, 2... Raised fabric, 3... Sheet-like elastic body, 4... Resin molded product, 5... Sheet for joining resin molded products, 8... Thread-like body.

Claims (1)

[Scope of Claims] 1. After the curing of the resin molded product is completed in a state where the surface of the resin molded product is pressed against the surface of the resin molded product before curing, the resin molded product is peeled from the surface of the resin molded product and the surface of the resin molded product is removed. A sheet for joining resin molded products formed on a rough surface.The base material is a woven fabric made of twisted yarns mainly consisting of short fibers, and the woven fabric is placed on the back side of this base material to a specified thickness. A sheet for joining resin molded products, characterized in that a sheet-like elastic body is provided in an embedded state. 2. The sheet for joining resin molded products according to claim 1, wherein the short fibers of the twisted yarn have a thickness of 2 denier and a length of 50 mm. 3. The sheet for joining resin molded products according to claim 1 or 2, wherein the sheet-like elastic body has adhesiveness. 4. A woven fabric is embedded to a predetermined thickness on the back side of a woven fabric in which the warp and weft are composed of twisted yarn consisting of short fibers alone, twisted yarn consisting of a mixed fiber of short fibers and long fibers, or both. Prepare a sheet for joining resin molded products provided with a sheet-like elastic body, and press the surface side of this sheet for joining resin molded products against the surface of the resin molded product before curing. After curing is completed, the sheet for joining the resin molded product is peeled off from the surface of the resin molded product, and the surface of the resin molded product is processed into a rough surface in which part of the resin of the resin molded product is raised in the form of threads. A method for joining resin molded products, characterized by joining the resin molded products using.