JP2005138379A - Composite molded product and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite molded product constituted so that a resin molded body and a rubber molded body having an undercut part are strongly bonded and integrated. <P>SOLUTION: A silicone rubber layer (B)3 showing adhesiveness with respect to a resin is bonded to the resin molded body (A)2 and the rubber molded body (D)5 having the undercut part is bonded to the silicone rubber layer (B)3 through a silicone adhesive layer (C)4 to constitute the composite molded product 1 wherein the resin molded body 2 and the rubber molded body 5 are integrated. By this constitution, the composite molded product wherein the resin molded body and the rubber molded body are strongly integrated can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composite molded body in which a resin molded body and a rubber molded body having an undercut portion are integrated, and a method for manufacturing the same.

  Generally, when a resin molded body and a rubber molded body are bonded, the surface of the resin molded product is treated with a solvent (primer treatment), an adhesive is applied to the surface, and the resin molded body is passed through the adhesive. However, since the rubber and the resin are inherently incompatible, their adhesion is generally low. Therefore, when a load is applied for a long period of time, there is a problem that peeling between the adhesive and the resin molding or / and peeling between the adhesive and the rubber molding occur.

  Thus, in recent years, silicone rubber has been developed that itself exhibits adhesiveness to a resin and can be bonded to a resin molded body without performing primer treatment (for example, Patent Document 1). In other words, this silicone rubber can be made into a molded body bonded to the resin molded body by molding itself in a state of being in contact with the resin molded body. If this silicone rubber is used, primer treatment or a separate adhesive can be produced. Thus, a composite body in which the resin molded body and the silicone rubber molded body are integrated with a relatively high adhesive strength can be produced. However, since this silicone rubber does not exhibit good adhesion to the resin unless it is in contact with the resin under high temperature and high pressure, the molding is inevitably press molding or injection molding.

  However, a rubber molded body having an undercut portion is hardly produced by press molding or injection molding. That is, since the rubber molded body is soft, it is possible to release it from the mold even if it is a rubber molded body having an undercut part by deforming the rubber molded body by air blow or the like. This is because it is very troublesome, and the rubber molded body may be damaged by deformation. In addition, if a complicated mold that is divided into three or more parts is used, even if it is a rubber molded body having an undercut portion, the molded body may be released relatively accurately, but the parting line A new problem occurs.

As described above, the silicone rubber (Patent Document 1) exhibiting adhesiveness to the resin does not exhibit good adhesiveness to the resin unless it is under high temperature and high pressure, and the molding is inevitably performed by press molding or injection molding. Will be done. The inventors of the present invention attempted to produce a composite molded body in which a resin molded body and a rubber molded body having an undercut portion are integrated using such silicone rubber (that is, the resin molded body is placed in a mold). A rubber molded body having an undercut portion was produced by molding silicone rubber in a state of being inserted into the rubber. However, since the obtained composite molded body has a resin molded body that is a rigid body, the composite molded body does not deform sufficiently even when air blow or the like is applied thereto, so that there is a problem that it cannot be released from the mold.
JP 2002-201445 A

  In view of the above circumstances, an object of the present invention is to provide a composite molded body in which a resin molded body and a rubber molded body having an undercut portion are firmly bonded and integrated, and a manufacturing method thereof.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, the resin molded body is bonded with a resin and a silicone rubber that exhibits adhesiveness (that is, the resin and the adhesive properties are maintained in contact with the resin molded body). The resin molded body is formed by adhering a rubber molded body with a silicone adhesive to a silicone rubber molded body (silicone rubber layer) exhibiting adhesiveness with the resin thus obtained. It has been found that the rubber molded body can be firmly bonded and integrated, and the present invention has been completed.

That is, the present invention
(1) A silicone rubber layer (B) showing adhesiveness to the resin is bonded to the resin molded body (A), and the silicone rubber layer (B) has an undercut portion through the silicone adhesive layer (C). A composite molded body in which a resin molded body and a rubber molded body are integrated, wherein the rubber molded body (D) is bonded,
(2) The composite molded body according to (1), wherein the resin molded body (A) is a molded body of PPE and the rubber molded body (D) is a molded body of silicone rubber,
(3) After forming a rubber layer by forming a rubber layer in a state where a resin and a silicone rubber exhibiting adhesiveness are in contact with the resin molding, a silicone adhesive is applied to the rubber layer, and then the silicone adhesive A method for producing a composite molded body in which a resin molded body and a rubber molded body are integrated, wherein the silicone-based adhesive is cured in a state where a rubber molded body having an undercut portion is brought into contact with the agent, And (4) The method according to (3) above, wherein the silicone adhesive is a room temperature curable silicone adhesive.

  In the present invention, the “rubber molded body having an undercut portion” is formed by a two-part mold having at least a concave portion or a convex portion on the outer peripheral surface and designed so as not to produce a parting line substantially. In such a case, when the concave portion or the convex portion is opened, the rubber molded body having a shape that engages with the convex portion or concave portion of the cavity of one mold and is held in the cavity. "Means.

  According to the present invention, it is possible to obtain a composite molded body in which a resin molded body and a rubber molded body having an undercut portion are firmly integrated. In particular, since the silicone rubber layer and the silicone adhesive layer interposed between the resin molded body and the rubber molded body exhibit rubber elasticity together with the silicone rubber layer, the external force is applied to the resin molded body and rubber. When applied to the molded body, it exhibits a vibration damping action, and the adhesion state between the resin molded body and the rubber molded body is stably maintained over a long period of time.

  In particular, when the resin molded body is a PPE molded body and the rubber molded body is a silicone rubber molded body, there is an advantage that a composite molded body having a balance between rigidity and flexibility can be easily obtained.

Hereinafter, the present invention will be described in detail.
FIG. 1 is a perspective view (FIG. 1 (a)) and a sectional view (FIG. 1 (b)) of a specific example of a composite molded body in which a resin molded body and a rubber molded body of the present invention are integrated. As shown in the composite molded body 1 of the example, the composite molded body of the present invention has a silicone rubber layer (B) 3 that adheres to the resin molded body (A) 2 and is bonded to the resin molded body (A) 2. A rubber molded body (D) 5 having an undercut portion is bonded to (B) 3 via a silicone adhesive layer (C) 4.

Resin molding (A)
In the present invention, the material (type of resin) and shape of the resin molding are not particularly limited, and various thermoplastic resin moldings can be used. Among them, an engineering plastic (engineering plastic) that can be compatible with a silicone-based adhesive without causing deformation at the time of pressing and heating during molding is preferable. Specifically, polymethylpentene (PMP), polybutene-1 (PB-1), polybutadiene (BDR), polystyrene (PS), acrylonitrile styrene resin (AS), acrylonitrile butadiene styrene resin (ABS), polyphenylene ether (PPE), polyacrylonitrile (PAN), polymethacrylstyrene (MS), methacrylic resin (PMMA), nylon (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyarylate (PAR), polyethersulfone (PES) and the like. Among these, a molded product of polyphenylene ether (PPE) is preferable, and when the resin molded product (A) is a molded product of polyphenylene ether (PPE), it is preferable in that appropriate rigidity can be obtained.

Rubber molded body with undercut (D )
In the present invention, the material (type of rubber) and shape of the rubber molded body having an undercut portion are not particularly limited, and various rubber molded bodies can be used. For example, molded products such as butyl rubber, chloroprene rubber, chlorosulfonated polyethylene, acrylic rubber, natural rubber, isoprene rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, ethylene-propylene rubber, urethane rubber, fluorine rubber, silicone rubber, etc. Can be mentioned. Moreover, the rubber molded body can use what was produced with various shaping | molding methods, such as press molding, injection molding, extrusion molding, blow molding, and gas assist molding. Among these, a molded body of silicone rubber is preferable, and when the rubber molded body (D) is a molded body of silicone rubber, higher adhesive force can be obtained with the silicone-based adhesive layer (C).

Silicone rubber layer (B) showing adhesiveness with resin
The silicone rubber layer exhibiting adhesiveness with the resin in the present invention is a known “silicone rubber exhibiting adhesiveness with resin, as described in Patent Document 1, which adheres to the resin by contacting the resin under high temperature and high pressure. It is a rubber layer formed (cured) by heating and pressurizing the “composition”.

  In the present invention, the silicone rubber (composition) described in Patent Document 1 is particularly preferable as the “silicone rubber (composition) exhibiting adhesiveness with resin” used for forming the rubber layer. That is, (a) a thermosetting organopolysiloxane composition, (b) a reinforcing silica fine powder, and (c) an epoxy equivalent of 100 to 5000 g / 1 mol and having at least one aromatic ring in the molecule. A silicone rubber composition containing an organic compound or an organosilicon compound as essential components is particularly preferable. The composition ratio of each component in the silicone rubber composition is (b) 1 to 100 parts by weight of reinforcing silica fine powder per 100 parts by weight of (a) heat-curable organopolysiloxane composition, and (c) epoxy equivalent is 100. The organic compound or organosilicon compound having at least one aromatic ring in the molecule at 0.1 to 50 g / 1 mol is 0.1 to 50 parts by weight. Moreover, patent document 1 can be referred as it is for the suitable aspect of each component (a)-(c) of the said silicone rubber composition in this invention. For example, the thermosetting organopolysiloxane composition of component (a) is preferably an addition reaction curable organopolysiloxane composition or an organic peroxide curable organopolysiloxane composition, particularly an addition reaction curable type. The organopolysiloxane composition is preferred. In this case, the addition reaction curable organopolysiloxane composition comprises (1) 100 parts by weight of an organopolysiloxane having an average of two or more alkenyl groups in one molecule and (2) an average of two or more silicon atoms in one molecule. 0.1 to 50 parts by weight of (3) addition reaction catalyst It is preferable that the catalyst comprises a catalytic amount, and the organic peroxide curable organopolysiloxane composition is ( i) Organopolysiloxane having an average of 2 or more alkenyl groups in one molecule 100 parts by weight (ii) Organic peroxide It is preferable that the catalyst consists of a catalyst amount.

  Preparation of the silicone rubber (composition) can be obtained by simply mixing the above-described components (a) to (c) and optional components evenly at room temperature. Preferably, the component (b) Among components (a), (2), (3), or components other than (ii) are heat treated with a planetary mixer, kneader, etc. in the range of 100 to 200 ° C. for 1 to 4 hours, at which point A processing agent may be added. Thereafter, the composition can be obtained by mixing the components (2), (3), or (ii), and (C) at room temperature.

  As the “silicone rubber (composition) exhibiting adhesiveness with resin”, a commercially available product can be used as it is, and preferred examples thereof include, for example, X-34-1547A / B, X-34-1625A / B (both trade names , Manufactured by Shin-Etsu Chemical Co., Ltd.).

  In the present invention, the method for forming the rubber layer (B), that is, the method for forming a “silicone rubber (composition) exhibiting adhesiveness with a resin” in a layer form is the “silicone rubber (composition) exhibiting adhesiveness with a resin”. The viscosity can be freely selected, and any method such as injection molding, press (compression) molding, injection molding, extrusion molding, or transfer molding may be employed. The curing conditions are usually 60-200 ° C. and thermoforming within a range of 10 seconds to 24 hours. The silicone rubber (composition) at the time of such heat molding is pressurized against the resin (resin molded body), and the contact pressure with respect to the resin is a known general molding condition in each molding method. Good.

  In the present invention, the thickness of the silicone rubber layer (B) is preferably a relatively thin thickness from the viewpoint of adhesion and freedom of design of a molded product molded by press molding. 0.0 mm is preferable, and 1.0 to 1.5 mm is more preferable.

Silicone adhesive layer (C)
In the present invention, the silicone-based adhesive constituting the silicone-based adhesive layer (C) contains a silicone resin, silicone rubber (RTV) or the like as a main material, and is heated (for example, about 80 to 100 ° C.) or at room temperature (10 to 10 ° C.). Under the condition of about 30 ° C., an elastic adhesive layer is formed after curing. In particular, since silicone RTV is cured at room temperature, it does not require heating and is excellent in thermal economy. Suitable silicone adhesives include, for example, KM-45-TM (manufactured by Shin-Etsu Chemical Co., Ltd., trade name).

  In the present invention, the thickness of the silicone-based adhesive layer (C) is preferably a relatively thin thickness from the viewpoint of adhesion and freedom of design of a molded product molded by press molding. 0.5 to 2.0 mm is preferable, and 1.0 to 1.5 mm is more preferable.

  An example of the composite molded body 1 shown in FIG. 1 is a groove (undercut) continuously formed on the outer periphery of a side surface of a cylindrical resin molded body 2 over the entire periphery of the side surface at a substantially intermediate position in the height direction of the outer surface. ) The cylindrical rubber molded body 5 on which 5A is formed is packaged, and the columnar resin molded body 1 and the cylindrical rubber molded body 5 are integrated. The composite molded body 1 of the example is suitable as a paper transport roller such as a paper discharge roller in an image forming apparatus such as a copying machine or a printer. In the case of the paper transport roller, the cylindrical resin molded body 2 includes It is particularly preferable to use a PPE molded body and use a silicone rubber molded body for the cylindrical rubber molded body 5.

When a composite molded body in which a molded body of PPE having the structure (shape) shown in FIG. 1 and silicone rubber are integrated is used for a paper transport roller, the outer surface (the surface in contact with the paper) is soft and the inside is hard. High paper conveyance force can be obtained.
Specifically, the dimensions of the paper transport roller are as follows: L1 in FIG. 1B is 10 to 30 mm, L2 is 8 to 10 mm, L3 is 20 to 30 mm, L4 is 1 to 5 mm, and L5 is 1 to 10 mm. is there.

The composite molded body of the present invention is produced by the following method.
2 (a) to 2 (c) are cylindrical rubber moldings in which grooves (undercuts) are formed on the outer periphery of the cylindrical resin molded body 1 shown in FIG. It is sectional drawing according to process which shows the manufacturing process of the composite molded object 1 which packaged the body 5 and integrated the columnar resin molded object 1 and the cylindrical rubber molded object 5. FIG.

As shown in FIGS. 2 (a) to 2 (c), in producing the composite molded body of the present invention, first, a silicone rubber (composition) showing adhesiveness with the resin is brought into contact with the resin molded body 2. In this state, the rubber layer 3 is formed by forming into a layer shape (FIG. 2A). As described above, this molding is performed by heat-curing the molten silicone rubber (composition) in contact with the resin molding. As described above, the molding (curing) conditions are usually performed at 60 to 200 ° C. for 10 seconds to 24 hours. At that time, it is necessary to bring the silicone rubber (composition) into contact with the resin molded body 2 with a contact pressure of about 10 to 100 kgf / cm ² . From the viewpoint of workability, economy, etc., using an injection molding device, the resin molded body 2 is inserted into the cavity of a mold having a cavity designed in a predetermined shape, and the silicone rubber (composition) is inserted. Preferably, it is molded by injection into the cavity.

  Next, a silicone adhesive 4a is applied to the silicone rubber layer 3 adhered to the resin molded body 2 (FIG. 2B). The method for applying the silicone adhesive is not particularly limited, and may be performed by a general-purpose method such as spin coating.

  Next, in a state where the rubber molded body 5 is in contact with the applied silicone adhesive 4a, the silicone adhesive 4a is cured, whereby the rubber molded body 5 is bonded to the rubber layer 3 via the silicone adhesive layer 4. Is bonded to complete the composite molded body 1 in which the resin molded body 2 and the rubber molded body 5 are integrated (FIG. 2C). As described above, when a silicone-based adhesive mainly composed of silicone RTV is used, the silicone-based adhesive can be cured at room temperature, does not require heating, and is excellent in thermal economy.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated more concretely, this invention is not limited by the following Example.

Example 1
A cylindrical molded body having a cross-sectional diameter (φ) of 14 mm and a height (L) of 10 mm made of PPE (Iupiace GAV2515 / manufactured by Mitsubishi Plastics Engineering Plastics) was prepared. This cylindrical molded body is inserted into a mold cavity of an injection molding apparatus, and a silicone rubber (X-34-1547A / B, manufactured by Shin-Etsu Chemical Co., Ltd.) showing adhesiveness with resin is heated and melted at 150 ° C. The product was injected into the cavity to form a 1 mm thick silicone rubber layer covering the entire side surface of the cylindrical molded body. The injection molding conditions were: injection time: 1 second, cooling time: 20 seconds, injection pressure: 140 kgf / cm ² , mold clamping pressure 25 tons, first mold temperature: 120 ° C., second mold temperature: 120 ° C. . Thereafter, the mold was opened, and a cylindrical molded body (in the state shown in FIG. 2A) whose entire circumference was covered with a silicone rubber layer having a thickness of 1 mm was taken out.

  Next, a silicone-based adhesive (KM-45-T / manufactured by Shin-Etsu Chemical Co., Ltd.) so as to have a substantially uniform thickness on the outer peripheral surface of a 1 mm thick silicone rubber layer covering the entire side surface of the cylindrical molded body. 1g (the state shown in FIG. 2 (b)), and this is a cylindrical shape having an outer diameter (φ) of 20 mm, an inner diameter (φ) of 16 mm, and a height (L) of 10 mm. A grooved cylindrical shape made of silicone rubber with a groove depth of 1 mm and a groove width of 2 mm (undercut) that is continuous across the entire circumference of the side surface at a substantially intermediate position in the height direction of the side surface. Insert into the inner space of the molded body, cure the silicone adhesive for 48 hours in an environment of temperature 25 ° C. and humidity 25%, and form a cylindrical cylinder with groove made of silicone rubber on the side of the cylindrical molded body made of PPE. Composite molded body (Fig. 2 ( c)) was completed.

  Two more composite molded bodies were produced in the same procedure as above, and the post-adhesion torque was measured for each of a total of three composite molded bodies by the following method to evaluate the adhesive strength.

[Measurement method of torque after bonding]
As shown in FIG. 3 (a), the composite molded body 1 is drilled with a drill or the like to form a through hole 13 consisting of a circular hole having a diameter (φ) of 8 mm whose axis coincides with the axis of the composite molded body 1. Next, the outer peripheral surface of the composite molded body 1 is ground from two opposite directions orthogonal to the axis of the composite molded body 1, and two opposing faces that are parallel to the axis and are equidistant from the axis. After forming the planes H1 and H2, a metal rod 14 having a diameter (φ) of 8.10 mm is press-fitted into the circular hole 13 (FIG. 3B). The distance (L) between the plane H1 and the plane H2 is 0.9 times L3 (L3 × 0.9) in FIG. 1, and here, 20 mm × 0.9 = 18 mm. Next, as shown in FIG. 3 (c), the composite molded body 1 having the planes H1 and H2 formed between the pair of pressure plates 11 and 12 separated by a distance (L) is installed, and the metal rod 14 Was rotated around its axis to measure the torque when the breakage occurred. In addition, destruction here means that adhesion | attachment will be released | released in the at least 1 location of the two adjacent layers in the layers 2-5 which comprise the composite molded object 1. FIG.

  The results are shown in Table 1 below. Interfacial delamination did not occur between the cylindrical molded body of PPE and the cylindrical molded body of silicone rubber, and the post-adhesion torque was 64-65 kgf · cm. In addition, since the cylindrical molded body of the silicone rubber after the test was damaged, the actual adhesive strength is considered to be larger than the values in Table 1.

Comparative Example 1
A cylindrical shaped body having a cross-sectional diameter (φ) of 16 mm and a height (L) of 10 mm made of PPE (Iupiace GAV2515 / Mitsubishi Resin Engineering Plastics) was prepared. Next, 1 g of a silicone-based adhesive (KM-45-T / manufactured by Shin-Etsu Chemical Co., Ltd.) is applied over the entire side surface of the cylindrical molded body so as to have a substantially uniform thickness. Inserted into the inner space of a grooved cylindrical molded body made of the same silicone rubber as that used, and cured with a silicone adhesive for 48 hours in an environment of a temperature of 25 ° C. and a humidity of 25%. A composite molded body in which a grooved cylindrical molded body made of silicone rubber was packaged and integrated on the side surface of the molded body was completed. Furthermore, two similar composite molded bodies were produced, and the post-adhesion torque was measured by the above-described method for each of a total of three composite molded bodies to evaluate the adhesive strength. The results are shown in Table 2 below. Interfacial peeling occurred between the cylindrical molded body of PPE and the cylindrical molded body of silicone rubber, and the torque after adhesion was 26 to 28 kgf · cm.

Comparative Example 2
A cylindrical shaped body having a cross-sectional diameter (φ) of 16 mm and a height (L) of 10 mm made of PPE (Iupiace GAV2515 / Mitsubishi Resin Engineering Plastics) was prepared. Next, after the primer (toluene) treatment is performed on the entire side surface of the cylindrical molded body, a silicone-based adhesive (KM-45-T / manufactured by Shin-Etsu Chemical Co., Ltd.) is applied so that the entire side surface has a substantially uniform thickness. 1 g was applied, and this was inserted into the inner space of a grooved cylindrical molded body made of the same silicone rubber as used in Example 1, and a silicone adhesive was applied in an environment of a temperature of 25 ° C. and a humidity of 25%. It was cured over time, and a cylindrical molded body made of PPE was covered with a cylindrical molded body with a groove made of silicone rubber to complete a composite molded body integrated. Furthermore, two similar composite molded bodies were produced, and the post-adhesion torque was measured by the above-described method for each of a total of three composite molded bodies to evaluate the adhesive strength. The results are shown in Table 3 below. Interfacial peeling occurred between the cylindrical molded body of PPE and the cylindrical molded body of silicone rubber, and the torque after adhesion was 35 to 40 kgf · cm.

It is the perspective view (FIG. 1 (a)) and sectional drawing (FIG.1 (b)) of an example of the composite molded object which the resin molded object of this invention and the rubber molded object which has an undercut part integrated. 2 (a) to 2 (c) are cross-sectional views showing processes for manufacturing the composite molded body of FIG. FIG. 3A to FIG. 3C are explanatory views of a method for measuring the post-adhesion torque of the composite molded body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite molded object 2 Resin molded object 3 Silicone rubber layer which shows resin and adhesiveness 4 Silicone type adhesive agent 5 Rubber molded object which has an undercut part

Claims (4)

  A rubber molded body in which a silicone rubber layer (B) exhibiting adhesiveness with a resin is bonded to the resin molded body (A), and the silicone rubber layer (B) has an undercut portion through the silicone adhesive layer (C). A composite molded body in which a resin molded body and a rubber molded body are integrated, wherein (D) is bonded.   The composite molded body according to claim 1, wherein the resin molded body (A) is a molded body of PPE and the rubber molded body (D) is a molded body of silicone rubber.   A rubber layer is formed by forming a rubber layer in a state where a resin and a silicone rubber exhibiting adhesiveness are in contact with the resin molded body, and then a silicone adhesive is applied to the rubber layer, and then the silicone adhesive is undercoated. A method for producing a composite molded body in which a resin molded body and a rubber molded body are integrated, wherein the silicone-based adhesive is cured in a state where a rubber molded body having a cut portion is brought into contact therewith.   The method according to claim 3, wherein the silicone adhesive is a room temperature curable silicone adhesive.

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