KR20100013569A - Injection molding method of metal and resin and the injection molding form - Google Patents

Abstract

PURPOSE: An injection molding method of different kinds of materials for improving injection accuracy is provided to obtain adhesion power by enabling welding due to high temperature of the injection. CONSTITUTION: An injection molding method of different kinds of materials for improving injection accuracy comprises following steps. A molded product is prepared(S10). The molded product is made of one among magnesium, stainless, aluminum, and titanium. Thermoplastic adhesive which generates twice curing reactions at different temperatures is prepared(S20). The thermoplastic adhesive is spread on the inner surface of the molded product(S30). The thermoplastic adhesive is heated at 60~150°C and is firstly cured(S40). The molded product is mounted inside the mold to contact the thermoplastic adhesive with resinous materials. The adhesive is secondly cured(S60). The molded product and the resinous material are cooled after being combined(S70).

Description

Injection molding method of heterogeneous materials with improved injection precision and injection molding thereof

The present invention relates to a dissimilar material joint injection molding method and an injection molding thereof, and more particularly, to prevent the overall thickness of the injection molding from increasing due to the adhesive, and to bond the metal molding and the resin molding in a simple process. The present invention relates to a dissimilar material joint injection molding method and an injection molded product capable of increasing injection precision as well as enabling automatic injection molding.

In many electronic products such as mobile phones, digital TVs, electronic dictionaries, digital cameras, and MP3s, metal moldings and resin moldings are often bonded. However, since the metal molding and the resin molding have different physical properties, adhesion is not easy.

The conventional method of adhering a metal molded product and a resin molded product is a method of adhering mainly using a heat fusion film. Specifically, the heat-sealed film is processed to meet the specifications of the metal plate and the injection molding attached to the inner surface thereof, the processed heat-sealed film is placed between the metal plate and the injection-molded product, temporarily fixed by heating, and then temporarily fixed. Since the metal plate and the injection molded product are thermally bonded using a heat fusion machine, this is a method of completing their adhesion.

However, the adhesion method by such a construction method had various problems. First of all, the heat-sealed film has to be processed to match the shape of the metal plate and the injection molding, and the work is complicated because more steps are required to temporarily fix the metal plate and the injection molding. In addition, manufacturing costs have been increased because a separate heat fusion machine must be provided to completely fix the temporarily fixed metal plate and the injection molding. Another problem of the conventional bonding method is that the adhesive strength of the metal plate and the injection molding is relatively weak, so that the metal molding and the resin molding are often separated from each other.

In order to solve this problem, a heat-adhesive structure of a metal molding and a resin molding and a method thereof (Korean Patent Publication No. 10-2007-0079604) have been developed.

It is provided with a protrusion formed to protrude to the outside on one side of the adhesive surface of the resin molding, forming a groove corresponding to the protrusion on the adhesive surface of the metal molding; Sanding the adhesive surfaces of the resin molding and the metal molding; Applying an adhesive to a contact surface of the sanded resin molding and the metal molding to a predetermined thickness; Pressing the adhesive surfaces of the resin molded article and the metal molded article coated with the adhesive to each other and pressing them at a constant pressure using a jig or the like; Heating the resin molded product and the metal molded product in the pressurized state under a constant condition in a heating furnace; It consists of the step of naturally cooling the heated resin material molding and metal material molding.

According to the conventional method for bonding a metal molding and a resin molding, the metal molding and the resin molding are easily peeled off because the adhesive strength is increased by sanding the adhesive surfaces, and the protrusions and the grooves are formed on the adhesive surfaces to improve the bondability. Can improve the problem.

However, in the conventional method of bonding the metal molding and the resin molding, as described above, the process is not only complicated, and the overall thickness of the structure is still thick due to the adhesive applied between the metal molding and the resin molding. And the precision of injection fell. In addition, the methods are difficult to automate due to the complexity of the process, it is a big problem that all processes can be performed by manual or semi-automatic methods.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide a heterogeneous joint injection molding method and an injection molding method for preventing the increase in the overall thickness of the injection molding due to the adhesive.

Another object of the present invention is a heterogeneous joint injection molding method and an injection method for bonding a metal molding and a resin molding made of any one of various materials such as magnesium, aluminum, titanium, and stainless steel in a simple process. To provide moldings.

It is still another object of the present invention to provide a heterogeneous material joint injection molding method and an injection molded product capable of realizing high injection precision.

It is still another object of the present invention to provide a heterogeneous joint injection molding method and an injection molded product capable of automating a bonding process of a metal molding and a resin molding.

In order to achieve the above object, the heterogeneous injection molding method of the present invention comprises preparing a metal molding made of any one of various materials such as magnesium, aluminum, titanium, stainless steel, and performing two curing reactions at different temperatures. After preparing the resulting thermosetting adhesive, the thermosetting adhesive is applied to the inner surface of the metal molding, and then the applied thermosetting adhesive is first cured by heating to a temperature of 60 to 150 ° C, and the first cured thermosetting adhesive is injected into the resin material. The metal material is placed in a mold to meet the mold, and the resin material is injected into the mold at a temperature of 250 to 340 ° C. so that the thermosetting adhesive applied to the metal material is caused to undergo a secondary curing at the injection temperature. After cooling the molding and the injection molded resin material Characterized in that binary luer.

Another feature of the heterogeneous injection molding method of the present invention is that the thermosetting adhesive is formed by mixing a copolyester, an adhesive reinforcing agent, a slip agent, a heat stabilizer, and a crosslinking agent.

Another feature of the heterogeneous injection molding method of the present invention is that the copolyester has a viscosity of 200 mPa · s to 1000 mPa · s and a low viscosity copolyester of 15% solution, and a viscosity of 2300 mPa · s to 2900 mPa · s. And a high viscosity copolyester which is a 15% solution.

Another feature of the heterogeneous injection molding method of the present invention is that the adhesion promoter is a mixture of kumarone-indene resin and alpha-methylstyrene / vinyltoluene resin. Is done.

Another feature of the heterogeneous injection molding method of the present invention, the crosslinking agent is an isocyanate-based curing agent.

Another feature of the heterogeneous injection molding method of the present invention, the thermosetting adhesive is a solvent 62 to 75 parts by weight, low viscosity copolyester 12 to 20 parts by weight, high viscosity copolyester 4 to 8 parts by weight, 6-10 parts by weight of a guarone-indene resin, 1-3 parts by weight of alpha-methylstyrene-vinyl fonruene resin, 0.1-0.3 parts by weight of slip agent, 0.1-0.3 parts by weight of heat stabilizer, crosslinking agent 1-2 The parts by weight are mixed.

Another feature of the heterogeneous injection molding method of the present invention, the solvent is made of any one of toluene and acetone.

Another feature of the heterojunction injection molding method of the present invention, the metal molding is made of any one material of stainless steel, aluminum, magnesium, titanium.

Another feature of the heterogeneous injection molding method of the present invention, the resin material is a polycarbonate (poly cabonate; PC), acrylonitrile-butadiene-styrene resin (ABS), acrylic resin, glass fiber reinforced polycarbonate, glass fiber It consists of a material of any one of reinforced acrylonitrile-butadiene-styrene resin (glass fiber reinforced PC).

The present invention as described above,

It can be applied to metal plates and resins made of any one of various materials such as magnesium, aluminum, titanium, and stainless steel, and can be obtained by high temperature at the time of injection, so that high adhesion can be obtained. It's extremely simple to implement automation. In addition, not only completely solves the problem that the adhesive layer is pushed out during the injection, which is a conventional problem, but also achieves slimming and precise injection molding of the metal molding and the resin molding.

In the heterojunction injection molding method of the present invention, as shown in FIGS. 1 and 2, the metal molding 1 is prepared (S10) and a thermosetting adhesive 2 is prepared to cause two curing reactions at different temperatures ( S20). Then, the thermosetting adhesive 2 is applied to the inner surface of the metal molding 1 (S30), and then the applied thermosetting adhesive 2 is heated to a temperature of 60 to 150 ° C. for primary curing (S40), and primary The metal molding 1 is seated (S50) in the mold 3 so that the cured thermosetting adhesive 2 meets the resin material 4 to be injected. Then, the resin material 4 is injected into the mold 3 at a temperature of 250 to 340 ° C. so that the thermosetting adhesive 2 applied to the metal material 1 is secondaryly cured (S60) at the injection temperature. It is made by causing the metal molding (1) and the resin material (4) to be injected is combined and then cooled (S70).

Here, the metal molding 1 consists of a magnesium plate material. The material of the metal molding 1 is not limited to magnesium, and may be made of any one of various materials such as aluminum, titanium, and stainless steel.

The thermosetting adhesive 2 for metals used in the present invention is formed by mixing a copolyester, an adhesive reinforcing agent, a slip agent, a heat stabilizer, and a crosslinking agent.

Among these, the base polymer of the thermosetting adhesive 2 for metals is a polyurethane resin based on copolyester. These copolyesters are low viscosity copolyethers with a viscosity of 200 mPa.s to 1000 mPa.s and 15% solution, and low viscosity with a viscosity of 2300 mPa.s to 2900 mPa.s and 15% solution. Copolyesters are mixed and used. The high viscosity copolyester serves to maintain the skeleton, and the low viscosity copolyester combines with the adhesive reinforcing agent described below at a high temperature to play a high temperature adhesive force.

As the tackifier resin, a coumarone-indene resin (hurcules Powder Co) and an alpha -methylstyrene / vinyltoluene resin (hurcules chemical Co) are used.

Of these, the Kumaron-Indene resin serves to improve the adhesive force of the entire thermosetting adhesive, and alpha-methylstyrene / vinyltoluene resin combines with the aforementioned low viscosity copolyester at high temperature to exert high temperature adhesive force. .

As the slip agent, PP powder (ultrafine hydrogilde 4500 PP poeder wax; royce) is used.

As a heat stabilizer, irganox-1010 (ciba-geiggy) is used.

As a crosslinking agent, an isocyanate-type hardening | curing agent is used. The crosslinking agent induces a crosslinking reaction at a low temperature to exert a low temperature adhesive force.

Appropriate content ratio of each component is as follows.

To 62-75 weights of solvents, 12-20 weight part of low-viscosity copolyesters, 4-8 weight part of high-viscosity copolyesters, 6-10 weight part of Kumaron-indene resins, and alpha-methylstyrene-vinylphone 1-3 weight part of luene resins, 0.1-0.3 weight part of slip agents, 0.1-0.3 weight part of heat stabilizers, and 1-2 weight part of a crosslinking agent are added.

Here, usable solvents include toluene, acetone and the like.

In the thermosetting adhesive 2 used in the present invention composed of the above components, the primary curing reaction occurs at a temperature of 60 ~ 150 ℃, the secondary curing reaction occurs at a temperature of 250 ~ 340 ℃.

The primary curing reaction is a role of a crosslinking agent, in which the thermosetting adhesive 2 is cured while causing a crosslinking reaction at a low temperature. When the primary curing reaction occurs, free transfer is possible because the thermosetting adhesive 2 applied to the metal molding 1 no longer flows along the surface of the metal molding 1.

If the primary curing of the thermosetting adhesive (2) is made at a temperature of less than 60 ℃, there is a fear that the primary cured thermosetting adhesive (2) is pushed out during injection. If the primary curing of the thermosetting adhesive (2) is made at a temperature in excess of 150 ° C, the strength of the primary cured thermosetting adhesive (2) is no longer increased, but only the energy cost is unnecessary. Therefore, the primary curing temperature of the thermosetting adhesive (2) is most preferably 60 ~ 150 ℃.

Secondary curing temperature of 250 ~ 340 ℃ is the injection temperature of the resin for conventional electronic components. If the injection is made below this temperature, the desired physical properties cannot be obtained. Components that adjust the curing temperature of the commercially available adhesive to the injection temperature of the resin are low viscosity copolyester, tackifier resins, such as guaron indene resin and alpha methyl styrene vinyl toluene resin. When the content of these components is out of the above-mentioned range, the curing temperature is out of the range, not only weakening or cracking the adhesive force, but also the amount of the curing agent is changed, thereby changing the adhesive force. Therefore, low viscosity copolyester, Kumaron indene resin, alpha methyl styrene vinyl toluene resin, 12 to 20 parts by weight of low viscosity copolyester, 6 to 10 parts by weight of the Kumaron indene resin, The mixing ratio of 1 to 3 parts by weight of alpha-methylstyrene-vinylfonluene resin should be maintained.

The metal molding 1 coated with the primary cured thermosetting adhesive 2 is seated in a designated interior of the mold 3 so that the thermosetting adhesive 2 applied to the metal molding 1 is injected into the mold 3. It is embedded to meet the resin material (4).

As such, when the resin material 4 is injected into the mold 3 on which the metal molding 1 made of any one of various materials such as magnesium, aluminum, titanium, and stainless steel is seated, the thermosetting property is maintained by a high injection temperature. The adhesive 2 undergoes a secondary curing reaction. When the secondary curing reaction occurs at a high temperature, the thermosetting adhesive 2 has a strong adhesive force and the heat resistance is significantly improved.

The metal molding 1 used in the present invention may be any one of aluminum, stainless steel, magnesium, titanium, and the like, and is applicable to all metal moldings 1 used in electronic parts, airplanes, ships, and the like.

When magnesium is used as the metal molding 1, it is preferable that the crystal grains of a magnesium plate material are 1-3 mm. Magnesium plate having such crystal grains is good in formability and thus advantageous to manufacture in various forms.

Plastic resin material (4) used in the present invention. Polycarbonate (PC), acrylonitrile-butadiene-styrene resin (ABS resin), acrylic resin, glass fiber reinforced polycarbonate (glass fiber reinforced PC), glass fiber reinforced acrylonitrile-butadiene-styrene resin (glass Resins used in electronic parts such as fiber reinforced ABS).

An embodiment of the present invention is as follows.

Thermosetting Adhesive Preparation Example 1

To 16 g of low viscosity copolyester (pearlstick 45-40 / 03) with a viscosity of 350 mPa.s and 15% solution, add 6 g of propylene glycol ether acetate, 44 g of toluene, and 16 g of acetone. After dissolution for 1 hour at a temperature of 60 ℃ 6g of high viscosity copolyester (pear / stick 45-40 / 27) was added and dissolved again for 1 hour. After dissolving, 6 g of guaron-indene (hercules power co. Picco 1-60), an adhesion promoter, was uniformly mixed and dissolved, followed by adding and dissolving 2 g of alpha-methylstyrene / vinyltoluene resin (hercules power co. Piccotex 100). .

After dispersing by adding 0.2 g of ultrafine hydrogilde 4500 PP powder wax (royce) as a slip agent, 0.2 g of diganox-1010 (ciba-geiggy) was added as a heat stabilizer, and then dispersed and cooled. 1.5 g was added to obtain an adhesive.

The thermosetting adhesive 2 thus obtained had a viscosity of 350 mPa · s (brookfield rvf sp. 2,20 rpm), a density of 20 ° C., 1,19 g / cm ³ , and a solid content of 32%.

(Different material bonding example 1)

The thermosetting adhesive (2) obtained in Example 1 of thermosetting adhesive was applied to the back surface of a stainless steel plate having a thickness of 0.5 tons with a thickness of 60 micrometers and dried at a temperature of 80 ° C. for 40 minutes, and a polycarbonate resin (glass fiber 30% mixed master batch resin) was injected into the back surface of the plate at a cylinder temperature of 285 ° C with an injection nozzle pressure of 135 Kg / cm ² .

At this time, the temperature of the mold 3 was 100 ° C, the injection speed was 95%, the injection time was 2 seconds, and the cooling time was maintained at 20 seconds. The thickness of the injection molded product was 500 micrometers (0.5 t).

As a result of checking the adhesive between the metal surface and the injected resin (PC), it was confirmed that there was no repulsion at all, and after separating the metal surface and the water surface to check the adhesive strength after 24 hours, the resin material molding (PC) was formed on the metal surface Excellent adhesion was torn at.

The results of the adhesion test after the cooling drop and the adhesion test after 74 hours of heat shock were also the same.

The tester used for the adhesion test was a push-pull gauge (standard speed: 10 cm / min), and the thermal shock test was held for 24 hours at -40 ° C and 72 hours in an oven maintained at 85 ° C for 2 hours. After leaving for 4 hours at room temperature, the adhesion was tested.

(Secondary Material Bonding Example 2 and Dissimilar Material Bonding Example 3)

Heterogeneous bonding was performed in the same manner as in Example 1, except that the transparent resin (PC) and acrylonitrile-butadiene-styrene resin (ABS resin) were used instead of the resin material (4). Was the same as By these examples it can be seen that the adhesive method of the present invention can be applied to various resins.

(Heteromaterial bonding example 4 to heterogeneous bonding example 6)

Heterogeneous bonding was carried out in the same manner as in Example 1, but instead of the stainless steel plate was used aluminium plate, titanium plate and magnesium plate, the result was the same as the heterogeneous bonding Example 1. By these embodiments it can be seen that the adhesive method of the present invention can be applied to various metal plates.

Thermosetting Adhesive Preparation Example 2

A thermosetting adhesive 2 was prepared in the same manner as in Preparation Example 1, except that the copolyester had a low viscosity copolyester (Pear / stick 45-40 / 05) having a viscosity of 400 mPa · s and a solution of 15%. ) Was used.

Thermosetting Adhesive Preparation Example 3

A thermosetting adhesive (2) was prepared in the same manner as in Preparation Example 1, except that the copolyester had a low viscosity copolyester (Pear / stick 45-40 / 08) having a viscosity of 800 mPa · s and a solution of 15%. ) Was used.

(Example 7 of dissimilar materials and Example 8 of dissimilar materials)

The adhesive strength was tested as in the heterogeneous bonding Example 1 using the adhesive obtained in Example 2 and thermosetting adhesive Preparation Example 3, the result was the same as in the heterogeneous bonding Example 1.

Thermosetting Adhesive Preparation Example 4

Thermosetting adhesive Preparation The adhesive was prepared in the same manner as in Example 1, except that the copolyester was a low viscosity copolyester (Pear / stick 45-40 / 11) having a viscosity of 1100 mPa · s and a solution of 15%. .

(Secondary Material Bonding Example 9)

The adhesive strength was tested as in the heterogeneous bonding Example 1 using the adhesive obtained in Example 4 of the thermosetting adhesive preparation, and the result of the lifting of the adhesive occurred in the thermal shock experiment.

Therefore, as the copolyester used when producing the thermosetting adhesive, it is preferable to use a low viscosity copolyester having a viscosity of 200 mPa · s to 1000 mPa · s and a 15% solution.

1 and 2 is a process diagram and a flow chart schematically showing a dissimilar material injection molding method of the present invention

* Description of the symbols for the main parts of the drawings *

1: metal molding 2: thermosetting adhesive

3: mold 4: resin material

Claims (4)

After preparing the metal molding (1) (S10) and preparing a thermosetting adhesive (2) causing two curing reactions at different temperatures (S20) and the thermosetting adhesive (2) of any one of magnesium, stainless steel, aluminum, titanium After coating (S30) on the inner surface of the metal molding (1) made of a material, and then the applied thermosetting adhesive (2) by heating to a temperature of 60 ~ 150 ℃ the first curing (S40), the first cured thermosetting adhesive (2) A resin material composed of any one of polycarbonate, acrylonitrile-butadiene-styrene resin, acrylic resin, glass fiber reinforced polycarbonate, and glass fiber reinforced acrylonitrile-butadiene-styrene resin (2) The metal material (1) is seated in the mold (3) to meet the (S50), and the resin material (4) is injected into the metal mold (3) at a temperature of 250 ~ 340 ℃ to apply to the metal material (1) Heat curing Injection is characterized in that the adhesive (2) is made to react to the secondary curing at the injection temperature (S60) to combine the metal molding (1) and the resin material (4) injected and then cooled (S70) Injection molding method for dissimilar materials with improved precision. The method of claim 1, wherein the thermosetting adhesive (2), Low viscosity copolyester with a viscosity of 200 mPa.s to 1000 mPa.s and a 15% solution, A copolyester made of a mixture of high viscosity copolyester with a viscosity of 2300 mPa.s to 2900 mPa.s and a 15% solution, an adhesive reinforcing agent made of a mixture of a kumaron-indene resin and an alpha-methylstyrene / vinyltoluene resin, and a slip And a heat stabilizer and a crosslinking agent, which is an isocyanate-based curing agent, in which the injection precision is improved. The method of claim 1, wherein the thermosetting adhesive (2), 62 to 75 parts by weight of a solvent composed of any one of toluene and acetone, 12-20 parts by weight of low viscosity copolyester, 4 to 8 parts by weight of high viscosity copolyester, With 6-10 weight part of Kumaron-indene resins, 1 to 3 parts by weight of alpha-methylstyrene-vinyl fonruene resin, 0.1-0.3 weight part of slip agent, 0.1-0.3 parts by weight of a heat stabilizer, The dissimilar material bonding injection molding method of improving the injection precision, characterized in that 1 to 2 parts by weight of the crosslinking agent is mixed. The heterogeneous joint-joint injection molded article of Claim 1 to 3 which improved the injection precision which consists of the injection molding method of any one of Claims 1-3.

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