JP2005162998A - Adhesive for bonding in mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive for bonding in a mold, preventing the adhesive applied to the surface of a metal insert from being flown away by a flowing pressure of a molten resin in an injection molding, bonding the metal insert with the resin by the heat of the molten resin in the molding and preventing the peeling off of the boundary of the metal and resin on releasing the mold. <P>SOLUTION: By using 2 kinds of curing agents consisting of a normal temperature curing agent and a latent curing agent, added to an adhesive epoxy base material applied to the metal insert for bonding the metal insert with the resin, the adhesive is semi-cured at normal temperature by the action of the former and prevents the adhesive from being flown away by the flowing pressure of the molten resin in the injection molding. The latter is activated by the heat of the molten resin in the injection molding to bond the resin with the metal insert, and prevents the peeling off of the boundary of the resin with the metal on releasing the resin from the mold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an adhesive for curing and bonding a thermoplastic resin and a metal insert using heat of a molten resin in a mold during injection molding.

  At present, thermoplastic resin metal inserts do not adhere to resin and metal, and therefore have a physical bonding function as a stopper to prevent them from slipping out by applying processing such as serration to the periphery.

  In addition, the bearing roller or the like in which the resin wraps around the outer periphery is covered with the resin so that the resin portion does not come off the bearing.

  On the other hand, various adhesives and primers have been tried for the metal insert in the mold and resin bonding, but the adhesive applied in advance is washed away by the flow pressure of the resin at the time of injection molding. At the time of releasing from the mold, it has not been put into practical use, such as peeling between the resin and the metal.

  In order to bond the metal insert to the resin, the adhesive applied by the molten resin flow pressure during injection molding is prevented from being washed away, and the metal insert and resin are bonded by the heat of the molten resin during molding. Is to prevent peeling between the resin and the resin.

Means for solving the problem

  In the present invention, in order to bond the metal insert and the resin, two types of curing agents, a room temperature curing agent and a latent curing agent added to the epoxy base material applied to the metal insert, are semi-cured at room temperature by the former function. To prevent the adhesive from flowing away at the flow pressure of the molten resin at the time of injection molding, the latter is made to work by the heat of the molten resin at the time of injection molding, the resin and the metal insert are bonded, and the resin is released from the mold. This prevents peeling between the resin and the metal.

  However, with regard to the room temperature curing agent, the solidification may be accelerated by activating the function at a temperature lower than the temperature at which the latent curing agent works and exceeding the room temperature, and may be in a semi-cured state.

  Further, the adhesion with the latent curing agent is not necessarily complete if there is no separation between the resin and the metal insert at the time of mold release, and may be cured in a thermostat after mold release.

The ratio of the inertial hydrogen of the room temperature curing agent to the epoxy group and the ratio of the latent curing agent are as follows.
Active hydrogen ratio of epoxy group / normal temperature curing agent is 1 / 0.2 to 1 / 0.5
The ratio of epoxy group / latent curing agent is 1 / 0.8 to 1 / 0.25.

  The thermoplastic resin used for molding is suitable for reinforced types such as urethane, polyamide, ABS, acrylic, styrene and alloys and glass based on them, which have sufficient adhesive strength with epoxy adhesive and modified epoxy adhesive. This is not the case as long as it is a thermoplastic resin that can provide sufficient adhesive strength.

  The thermoplastic resin may contain dyes or pigments and various additives as necessary, for example, anti-aging agents, antioxidants, light stabilizers, nucleating agents, ultraviolet absorbers, release agents and the like.

  The reaction temperature of the latent curing agent is set to 100 ° C. or higher to prevent reaction at room temperature.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not restrict | limited at all by these Examples, unless the summary is exceeded.

The ISO dumbbell for tensile test shown in FIG. 1 uses carbon steel as the metal insert 1, and the following adhesive is applied to the connection portion 2 of the metal insert 1 6 hours before molding, and the remaining half of the dumbbell, resin 3 Is molded from thermoplastic polyurethane by injection molding.
1 / 0.5 equivalent ratio of epoxy group / active hydrogen of normal temperature curing agent
1 / 0.5 equivalent ratio of epoxy group / latent curing agent

  The result of carrying out a tensile test using this dumbbell is shown in FIG.

  It was confirmed that sufficient strength was secured for all samples.

ISO (10x4mm cross section) dumbbell for tensile test Tensile test results

Claims (1)

BPA-type or BPF-type epoxy resin as the main agent, further modified with urethane or rubber, polyamide polyamine or modified aliphatic polyamine as normal temperature curing agent, DICY or imidazole-based latent curing agent as latent curing agent, Furthermore, the equivalent ratio of the active epoxy in the adhesive epoxy group / curing agent for room temperature mixed with the modified ones in the following ratios: 1 / 0.2 to 1 / 0.5
The equivalent ratio of epoxy group / latent curing agent is 1 / 0.8 to 1 / 0.25.

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