JPH079484A - In-mold decorating injection molding method and decorative film used therefor - Google Patents

Abstract

PURPOSE:To prevent occurrence of deformation, flow, breakage, and the like in a film by a method wherein in in-mold decorating injection molding by heating a resin to be injected to at least a melting point of a decorative film, a film having a specific ratio of a heat conductivity to a thickness is used as the decorative film, and a mold is cooled to a specific temperature or lower. CONSTITUTION:In in-mold decorating injection molding in a condition of TN>=TM where a temperature of a melt resin to be injected is TN deg.C and a melting point of a decorative film is T. 'C, a film meeting a requirement of kappa/DELTAx>=3.0X10<-2>cal/ sec.cm<2>. deg.C is used as the decorative film where kappa is a heat conductivity (cal/ see.cm<2> deg.C) of a film and DELTAx is a thickness (m) of a film. In molding, a surf ace temperature of a mold is set to a temperature lower than both the heat deforming temperatures of the decorative film and the injection resin. In this manner, a heat transferred from the melt resin to the decorative film can be rapidly released to the mold, whereby the decorative film can be prevented from being excessively increased in temperature even in a molding condition of TN>=TM.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding simultaneous painting method and an improvement of a painting film used therefor.

[0002]

2. Description of the Related Art The simultaneous injection molding painting method is a method in which a painting film inserted between male and female molds at the time of injection molding is integrated with a molten resin to be injected and injected into a cavity to paint on the surface of a molding. This method is called a laminate printing method or a transfer printing method, depending on the painting film used. That is, in the laminate printing method, a laminated painting film (laminate film) is used in which all layers of the painting film consisting of the base film and the picture layer are integrally bonded to the surface of the molded body to form a decorative layer, and transfer printing is performed. In the method, a transfer film is used in which only the base film of the painting film integrated on the surface of the molded body is peeled off, and the transfer layer such as the pattern layer is left on the molded body side to form a decorative layer.

An example of the simultaneous injection molding painting method using a transfer film will be described with reference to FIGS. 1 and 2 (see also Japanese Patent Publication No. 4-42172). This device 60 includes a female die 70 and the female die 7.
And a male die 80 arranged to face the side of 0.
The female mold 70 is provided with a cavity 72 corresponding to the outer shape of the molded body to be obtained, and an intake hole 74 opening to the cavity 72 is provided therein, and the male metal is moved by the advancing / retreating device 75 including a cylinder or the like. The mold 80 can be moved back and forth in a direction of approaching and separating from the mold 80. Further, the male die 80 has a core portion 82 to be inserted into the cavity 72, and a molten resin pouring hole (gate) 84 is provided therein. Then, if necessary, a heating plate 90 is disposed between the female die 70 and the male die 80 so as to be able to move forward and backward.

In order to perform painting simultaneously with injection molding using such an apparatus 60, first, a transfer film 100 for painting is placed opposite to the side of the female mold 70, and this transfer film 100 is used as necessary. To heat and soften it on the hot platen 90, then sandwich the transfer film 100 between the female mold 70 and the hot platen 90 to close the opening surface of the cavity 72, and
A vacuum is evacuated through the intake hole 74 provided in the hot plate 90 and compressed air is supplied through the ventilation hole provided in the heating plate 90.

As a result, the transfer film 100 is stretched along the inner peripheral surface of the cavity 72 and comes into close contact with it, as shown in FIG. Note that this step is generally called preforming. Subsequently, with the hot platen 90 retracted, as shown in FIG. 2, the female die 70 is moved forward to be merged with the male die 80 to perform mold clamping, and then the female die 70 and Injection molding is performed by injecting and filling molten resin through a pouring hole 84 provided in the male mold 80 into a cavity space formed with the male mold 80.

As a result, the transfer film 100 in the female die 80 is integrally attached to the injected resin (molded body P),
When the mold is opened after completion of the injection molding, the molded product having the transfer film 100 attached to the outer surface is taken out from the inside of the mold. In a subsequent step, only the base film of the transfer film 100 integrated on the outer surface of the molded body S is peeled off, and a transfer layer such as a pattern layer is left on the molded body S side to form a transfer layer, thereby painting Is completed.

As can be seen from the above description, the transfer film 100 is used in such an injection molding simultaneous painting method.
It is an important requirement for obtaining a molded product that it can be closely adhered by being stretched along the inner peripheral surface of the cavity 72 (moldability). This also applies to the case where a laminate film is used instead of the transfer film, and particularly in the case of using a deep metal mold,
This is an important requirement because the transfer film or laminate film is deeply drawn.

Conventionally, in order to obtain preferable moldability,
As the base film of the transfer film and the laminate film, polyvinyl chloride (PVC), which has good thermoformability,
Acrylonitrile / butadiene / thretin copolymer (A
BS) or the like, but depending on the combination of the base film and the injection resin used, the injection resin temperature T _N (substantially as described below) rather than the melting temperature or melting point T _M of the base film during injection molding. In many cases, the nozzle temperature of the injection-melting resin becomes higher (T _N ≧ T _M ). (See Tables 1 and 2)
When a VC film is used and an ABS resin is used as the injection resin, the melting point or melting temperature T _M of PVC is about 170 ° C., and the nozzle temperature T _N during normal molding of the ABS resin is
Is about 200 to 260 ° C., and T _N ≧ T _M ). In that case, the painting film is apt to be deformed, flowed, or torn due to the heat and pressure of the injected molten resin. It was

That is, the heat of the injection resin is transferred to the pattern surface of the painting film during the injection molding, but if the cooling from the mold is performed efficiently at that time, the injection resin contacts the painting film. At the same time, the resin solidifies, and it is possible to prevent deformation, flow, breakage, etc. of the painting film, but when cooling from the mold is insufficient or especially when the painting film is thick and has low thermal conductivity. In some cases, the injection resin may not solidify rapidly and the resin may move between the surface of the painting film and the printing ink that has been softened by heating, and the printing ink is washed away by the resin. Furthermore, in a place where the shear heat generation is large in the mold (where the resin flows from a wide place to a narrow place), the resin once solidified may melt and flow again, and the calorific value itself is large. From things such as
In the case of a painted film using a film with large thermal deformation (good moldability) such as polyvinyl chloride (good formability) as a substrate film, the film itself deforms and begins to flow (melt). .

In order to eliminate such inconvenience, for example, as disclosed in Japanese Patent Publication No. 2-4080, Tmk
It has been proposed to use a highly biaxially stretched polyester film or a biaxially stretched nylon film as a base film for a painting film (transfer film). In this case, as shown in Tables 1 and 2, T _N < It becomes possible to perform molding under the condition of T _M.

Further, as described in Japanese Utility Model Publication No. 4-5358, transfer is made by bonding a film of nylon 66 or the like having higher heat resistance than polyvinyl chloride onto the surface of polyvinyl chloride having good thermoformability. It has been proposed to use it as a base film of a film, and to use the film side having high heat resistance during molding as the side in contact with the injection-melting resin.

[0012]

The above-mentioned proposals solve the problems such as deformation, flow, and tear of the painting film, which tend to occur in the painting film at the time of molding, to some extent, but the biaxial stretching is performed. A polyester film or a biaxially stretched nylon film is inferior in thermoformability to polyvinyl chloride, and has a large unevenness in the molding die, a small radius of curvature R, a large drawing ratio, etc. There are cases where the film does not follow the shape of the mold sufficiently, and in extreme cases, the film is damaged. Further, depending on conditions such as the shape and size of the mold or the type of injection resin, there may be a case where the molding must be performed under the condition of T _N ≧ T _M.

Further, in the case where a film such as nylon 66 having a high heat resistance is laminated on the surface of polyvinyl chloride, two different films are laminated, so that the manufacturing process is complicated and the material cost is increased. The cost tends to be high, and the heat-resistant film such as the laminated nylon is inferior in heat deformability to the polyvinyl chloride film, so that the good thermoformability inherent in the polyvinyl chloride film cannot be fully utilized. ing. In the case of this painting film, as in the case of the above-mentioned one, in some cases, it may be necessary to form under the condition of T _N ≧ T _M (see Table 1 and Table 2).

An object of the present invention is to eliminate the above-mentioned disadvantages of the painting film used in the conventional injection molding simultaneous painting method and the injection molding simultaneous painting method using the painting film. More specifically, the temperature of the molten resin to be injected is T _N [° C.], the melting point of the base film of the painting film (or the melting temperature) while maintaining sufficient moldability. ) Is T _M [° C.], even if injection molding is performed under the condition of T _N ≧ T _{M, the} pattern or film may be deformed, flowed, or torn due to heat or pressure of the injection-melting resin. Disclosed is a non-painting film and a simultaneous injection-molding painting method using the same. Another object of the present invention is to disclose a painting film which is easy to manufacture and can reduce the material cost.

[0015]

In order to solve the above problems and achieve the object, the present inventors have conducted many experiments and researches on the injection molding simultaneous painting method. First, decorating film in an injection-mold painting, assume that it is impossible to avoid the case where forced to perform molding in the conditions of T _N ≧ T _M, the molding conditions of T _N ≧ T _M In order to prevent deformation, flow, breakage, and the like, it was attempted to increase the thickness Δx of the base film of the painting film. As a result, the heat capacity of the base film is increased, the rate of temperature rise is decreased, and the strength of the base film itself is increased, so that it is considered that deformation of the film can be eliminated. However, from the experiments, satisfactory results could not be obtained by simply increasing the thickness Δx of the base film. It was presumed that the thicker base film had a lower temperature gradient between the front and back of the film, lowering the heat flow density even with the same thermal conductivity, and increasing the film temperature more rapidly.

Therefore, further experiments and logical consideration were continued. First, as shown in FIG. 3, a model in which only a unit cross-section area is taken out of a state in which a painting film is sandwiched between a mold and a molten resin filled by injection is considered. That is, in the painting film F, (melt resin R)
→ (Painting film F) → (Mold C) Heat flow density Q _F [cal / cm ² .sec] is the thermal conductivity κ of the painting film, temperature gradient ∂T / ∂x, melting Assuming that the resin temperature T _N , the mold temperature T _o , and the painting film thickness Δx, Q _F = κ · ∂T / ∂x≈κ (T _N −T _o ) / Δx (1)

On the other hand, when the heat flow density flowing from the molten resin into the painting film is Q _IN and the heat flow density flowing out from the painting film to the mold is Q _OUT , the three factors of the molten resin, the painting film and the mold are obtained. Since the conditions such as thermal conductivity, specific heat, and temperature are also different, Q _IN ≠ Q _F ≠ Q _OUT is not generally in the process of molding, and the heat quantity corresponding to Q _IN -Q _OUT is per unit time. It is stored in the painting film and the temperature rises. This temperature rise ΔT is ΔT = (Q _IN −Q _OUT ) / CρΔx, where C [cal / ° C.g] is the specific heat of the painting film and ρ [g / cm ³ ] is the density. (2) Looking at the contribution of the film thickness Δx to the film temperature, it can be seen that the equations (1) and (2) act in opposite directions.

That is, considering the case where the film thickness Δx is reduced (thinned) now, according to the formula (1), the amount of heat entering the film is promptly discharged to the mold side in the direction of decreasing the temperature. From (2), the heat capacity (CρΔx)
It can be seen that the value increases as the temperature decreases. On the contrary, considering the case of increasing (thickening) the film thickness Δx, the heat quantity entering the film stagnates and the temperature rises according to the formula (1), but the heat capacity (CρΔ
It can be seen that x) increases and the temperature decreases.

In either case, the temperature of the painting film is determined by the contribution of the effect of equation (1) and the effect of equation (2), whichever is larger. By comprehensively evaluating the contributions of both equations (1) and (2), the spatial (x, y, z) distribution of temperature T and time
In order to accurately obtain the change due to (t), the heat conduction equation κ / cρ ∇ ² T = ∂T / ∂t ··· (3) should be solved under given initial conditions and boundary conditions. However, it is difficult to solve the complicated mold shape and the inflow state of the molten resin.

Therefore, the present inventors have proposed various κ, C,
A resin film having ρ and Δx is molded at various injection resin temperatures T _N and mold temperatures T _o , and experimentally set conditions for preventing problems such as deformation, flow and flow of the painting film. results obtained, contrary to the expected first, maintaining the molds surface temperature to a temperature lower than either of the painting heat distortion temperature [T _D1] and heat distortion temperature of the injected resin film [T _D2] When molded in this state, the resin film normally used and the usual injection conditions (ie, κ = 1 ×
About 10 ^{−4 to} 13 × 10 ⁻⁴ [cal / sec.cm. ° C.], Δx =
10 to 500 μm, C = 0.2 to 0.6 [cal / ° C.g],
ρ = 0.9 to 1.5 [g / cm ³ ], T _N = 180 to 280
C, T = about 100 to 280 ° C.), the formula (2)
It has been found that the contribution of the equation (1) is larger, and that the film thickness Δx is rather thinner than what is conventionally assumed, the deformation such as the flow due to the injection molten resin is reduced.

The thickness Δx also depends on the thermal conductivity κ of the film, and κ / Δx is a parameter that governs deformation such as flow of the painting film. Generally, κ / Δx ≧ 3.0 × 10 ^{At -2} [cal / sec.cm ^2. ° C], even if T _N ≥T _M , deformation or the like occurs, which causes problems in the design such as the painting film and the design given by it. It was found that the problem can be solved.

The present invention is based on the above findings, and basically, the temperature of the molten resin to be injected is T _N [° C.],
When the melting point (or melting temperature) of the painting film is T _M [° C.], in the simultaneous injection molding painting method under the condition of T _N ≧ T _M , κ / Δx ≧ 3.0 as the painting film.
× 10 ^-2 [cal / sec.cm ^2. ℃] (κ: thermal conductivity of film [cal / sec.cm ^2. ℃], Δx: film thickness [cm]) Select a painting film and used, and, characterized in that molding in a state of being cooled to a temperature lower than any of the thermal deformation temperature of the decorating film molds surface temperature [T _D1] and thermal deformation temperature of the injected resin [T _D2] An injection molding simultaneous painting method is disclosed.

As a result, the amount of heat coming from the molten injection resin into the painting film can be quickly released to the die side, and in the case of simultaneous painting by injection molding under the condition of T _N ≧ T _M , However, excessive temperature rise of the painting film is prevented, and deformation, flow, breakage, etc. of the painting film are surely prevented. The painting film used may be a transfer film or a laminated film.

Both the transfer film and the laminated film have a decorative layer and a transfer pattern layer on the base film, and these layers have melting points (or melting temperatures) T _M ', different from those of the base film. It has a thermal conductivity κ ′, a thickness Δx ′, and a thermal deformation temperature [T _D ′], respectively. However, since these layers are usually smaller in thickness, volume, etc. than the base film, the decorative layer and the transfer pattern layer are ignored and only the base film is used when determining the above values as a painting film. In practice, it does not matter even if it is done according to the value.
However, when the contribution of the decorative layer and the transfer pattern layer cannot be ignored, the entire painting sheet including these layers,
Use each value.

Further, in the present invention, the painting film
Deformation temperature of aluminum (ASTM-D-648, 18kg / cm²)
T_DThen, a painting film inserted between both molds
To T _D≤T_PRE<T_M, Temperature T_PREHeated to (℃)
After softening, vacuum forming, pressure forming, or vacuum pressure forming
Pre-form the painting film so that it follows the surface of the female mold.
Shape it, then close both molds and tighten the molds
Good, good injection even when deep drawing is required
Simultaneous molding and painting can be performed.

The present invention also provides a coating layer on the substrate film.
A film for simultaneous injection molding and painting
The thermal conductivity κ [cal / sec.cm. ° C.] of the base film,
Thickness Δx [μm], melting point (or melting temperature) is T
_M[° C], the temperature of the molten resin to be injected is T _N[° C]
When T_M≤T_N, Κ / Δx ≧ 3.4 × 10^-2(Cal / sec.
cm²Filling for simultaneous injection molding painting
Will also disclose. A single layer film is sufficient for this film
Because it can achieve the purpose, it is easy to manufacture.
Moreover, the manufacturing cost can be reduced.

In the present invention, the injection molten resin temperature T _N should be considered as a phenomenon, and the resin temperature in the vicinity of the painting film should be originally used, but it is difficult in practical use (thermocouple is used in the cavity). It is not impossible to measure the temperature of the injected molten resin by fixing it to a place a little away from the painting film and injecting the molten resin into it, but it is difficult to collect the thermocouple after molding, and the thermoelectric Molded products with a buried pair are defective products.) As a result of various studies, if the resin temperature measured at the nozzle of the injection molding machine is T _N , measurement is easy and near the painting film. It was also found that there is a good correlation with the resin temperature immediately after reaching the temperature. Therefore, in the present specification, unless otherwise specified, the injection molten resin temperature T _N refers to the nozzle temperature.

Further, as the heat deformation temperature T _D2 of the heat deformation temperature T _D1 and injection resin decorating film, ASTM-D-64
No. 8 18.6 [kg / cm ² ] heat distortion temperature, ASTM-D-64
8 can be evaluated by the heat distortion temperature of 4.6 [kg / cm ² ] and the ViCat softening point temperature. In the case of the present invention, since the heat-softened resin base material film is formed into a mold shape, ASTM-D-
A heat distortion temperature of 18.6 [kg / cm ² ] of 648 is preferably adopted.

In the present invention, different T _M values are used depending on the type of target film. That is, generally, a resin having a high crystallinity has a clear melting point, and in this case, the melting point temperature is T _M. Amorphous or low crystallinity resins gradually increase in fluidity with increasing temperature and do not have a clear liquid-solid phase transition temperature.
In this case, the lowest temperature at which the liquid has sufficient fluidity and can be considered to be obviously liquid is defined as the T _M value. Usually, this is what is called the melting temperature.

In the present invention, the painting film may be of two modes, that is, a laminate film and a transfer film as described above. The laminate film is a film on which a decoration is applied by a method such as printing, painting, embossing, metal vapor deposition, and the like, which is adhered and integrated with the surface of the molded product simultaneously with injection molding, and used as it is as a final form. It is optional whether the decorative layer is provided on the base film side or on the side opposite to the molded product, but normally the decorative layer is laminated (bonded) toward the molded product side and the base film is used as the surface protective film. To use. The transfer film has a base film as a support film, and a transfer pattern layer is formed on the support film with an adhesive force such that it can be peeled off.The transfer pattern layer is formed by printing, painting, vapor deposition or the like. It In the case of a transfer film, it is inserted between the molds so that the transfer layer side always faces the injection resin side (also the cavity side or the molded product side). After the transfer film is bonded to the surface of the molded product at the same time as the injection molding, only the base film (or the base film / release layer) is peeled off to leave only the transfer pattern layer on the surface of the molded product.

Representative examples of combinations of the injection-melting resin and the base film of the picture film, which the present invention effectively functions, are shown in Tables 1 to 4 (in particular, Δ in Tables 3 and 4).
x). The abbreviations of resin names in the table are as follows. PVC Polyvinyl chloride PS Polystyrene ABS Acrylonitrile-butadiene-styrene copolymer AS Acrylonitrile-styrene copolymer PP polypropylene PMMA polymethylmethacrylate NYLON-66 nylon-66 PBT polybutylene terephthalate PET polyethylene terephthalate

In the present invention, the cooling temperature of the mold can be maintained at a predetermined temperature by flowing cooling water into the mold. In addition, the mold can be cooled efficiently by iron, iron alloy of stainless steel, copper, copper alloy such as brass,
It is desirable to use a metal having a high thermal conductivity such as, for example, (plating the surface with chromium or the like if necessary). The set temperature is lower than the heat distortion temperature of the base film of the painting film and the injection resin so that the molding can be completed and the mold can be opened and the molded product and the painting film adhered to it can be taken out. Set to. Although lowering the mold cooling setting temperature is more effective in suppressing the flow of paint film due to heat, etc., the injection resin will not be cooled into the mold by excessive quenching in the mold. In order to prevent poor flow, generation of weld lines, residual stress inside the molded product, etc., it is preferable to keep the mold temperature at room temperature (about 20 ° C.) or higher.

In the practice of the present invention, if the thickness of the painting film becomes extremely thin, the film is likely to be torn, and wrinkles and other deformations are likely to occur. Therefore, it is necessary to secure a film thickness that does not cause such a problem.
The lower limit of x varies depending on the type of resin in the film, how to handle the film, and molding conditions (temperature, pressure), but normally it is desired to secure at least 20 μm.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

EXAMPLES The present invention will be described below with reference to examples. Example and Comparative Example 1 The following films were prepared. (A) Thickness of semi-rigid type containing 10 parts by weight of plasticizer
50 μm (= 0.5 × 10 ^-2[Cm]) PVC film
(Example of the present invention). PVC film: melting point (or melting temperature) T_M= 170
℃, heat distortion temperature T_D1= 70 ° C, thermal conductivity κ = 3.4 × 10
^-Four~ 4.0 x 10^-Four[Cal / sec.cm. ° C] That is, κ / Δx = 3.4 × 10^-Four~ 4.0 x 10^-Four/ 0.
5 x 10^-2= 6.9 x 10^-2~ × 8.1 × 10^-2＞ 3.0 × 1
0^-2(Cal / sec.cm². ° C] (b) Same PVC film as (a) but with a thickness of 1
50 μm (= 1.5 × 10 ^-2[Cm]) (comparative example).
This film has κ / Δx = 2.3 × 10^-2~ 2.7 × 10
^-2(Cal / sec.cm². ° C], and the value is 3.0 × 10
^-2(Cal / sec.cm². ° C].

The films of (a) and (b) were printed in the following order to obtain a transfer film. (1) Release layer urethane coating amount 3 g / m ² (dry) (2) Release layer acrylic coating amount 1 g / m ² (dry) (3) Pattern × 3 colors acrylic, vinyl chloride, coating amount 1 g / m ² (Dry) (4) Heat-sensitive adhesive layer Acrylic coating amount 1 g / m ² (dry) This transfer film was placed in a female mold with the transfer pattern layer facing the cavity, and heated from the transfer pattern layer side (about 10
(0 ° C.), and vacuum pressure molding was performed along the inner surface of the mold so as to adhere them.

Next, while maintaining the mold surface temperature at 40 ° C., the molten PS resin (Sumibrite M566) (heat deformation temperature T _D2 = 70 ° C.) was applied to the nozzle temperature T _N 230 ° C. from the male mold side. (> T _M = 170 ° C. (melting point (or melting temperature of PVC) of PVC). After cooling, the molded product was taken out and observed. In the case of the film of the result (a), the resin injection gate portion was also included.
The pattern ink did not flow or deform, and a good transferred pattern was formed. In the case of the film (b), the vicinity of the resin injection gate was missing in a circular shape. In addition, in the portion where the molding shape was narrow, the ink flowed and the film surface was damaged.

Example and Comparative Example 2 The following films were prepared. (A) PM with a thickness of 100 μm (= 1.0 × 10 ^-2 [cm])
MA film (Example of the present invention). PMMA film: melting point (or melting temperature) T _M = 160
° C, heat distortion temperature T _D1 = 68 ° C, thermal conductivity κ = 4.0 × 10
^{−4 to} 6.0 × 10 ⁻⁴ [cal / sec.cm. ° C.] That is, κ / Δx = 4.0 × 10 ⁻² to × 6.0 × 10 ⁻² >
3.0 × 10 ^-2 [cal / sec.cm ^2. ℃] (b) The same PMMA film as (a), but with a thickness of 250 μm (= 2.5 × 10 ^-2 [cm]) (Comparative example). This film has κ / Δx = 1.6 × 10 ^{-2 to} 2.4
× 10 ^-2 [cal / sec.cm ^2. ℃] and its value is 3.0 × 1
It is smaller than 0 ^-2 [cal / sec.cm ^2. ℃].

In the same manner as in Example and Comparative Example 1, injection molding was carried out in the same manner as in Example and Comparative Example 1 by forming (3) only three colors of the pattern among the printing layers of Example and Comparative Example 1 on the film of (a) and (b) to form a laminated film. Simultaneous painting was performed, and after cooling, the molded product was taken out and observed. In the case of the film of the result (a), including the resin injection gate part,
The pattern ink did not flow or deform, and a good pattern was formed. In the case of the film of (b), the ink near the resin injection gate flowed, and the appearance was light.

[0043]

EFFECTS OF THE INVENTION According to the present invention, although it has sufficient moldability, the pattern or film is not deformed, flowed, or broken by the heat or pressure of the injection molten resin, and the production is easy. In addition, it is possible to obtain a painting film that can reduce the cost of materials and a molded article painted with the painting film.

[Brief description of drawings]

FIG. 1 is a diagram showing a molding process by an injection molding simultaneous painting method.

FIG. 2 is a diagram showing a molding process by an injection molding simultaneous painting method.

FIG. 3 is a diagram illustrating heat transfer between a painting film, a mold, and a molten resin that is injection-filled.

[Explanation of symbols]

70 ... Female mold, 72 ... Cavity, 80 ... Male mold, 84
... Gate, 90 ... Hot platen, 100 ... Transfer film, P ... Molten resin

Claims (6)

[Claims] 1. A female mold and a male mold that form a cavity space are opened, a painting film having at least a picture layer and a base film is inserted between the two dies, and the two dies are placed between the painting films. The mold is closed and clamped, the molten resin is injected and filled into the cavity from the gate, and by cooling and solidifying, the painting film is bonded and integrated on the surface of the injected resin, and then both molds are opened. In the simultaneous injection-molding painting method for obtaining a molded article whose surface is painted, the temperature of the molten resin to be injected is T _N [° C], and the melting point (or melting temperature) of the painting film is T _M [° C]. ] As T
_When a molten resin having a temperature T _N of _N ≧ T _M is injected, and the thermal conductivity κ [cal / sec.cm ^2. ° C.] and the thickness Δx [cm] of the painting film are used, the painting film is κ /
The use of a painting film satisfying the condition of Δx ≧ 3.0 × 10 ⁻² [cal / sec.cm ^2. ° C.], and the surface temperature of both molds is set to the heat deformation temperature [T
_D1 ] and the heat distortion temperature [T _D1 ] of the injection resin, and the molding is performed by cooling to a temperature lower than both of them. 2. A transfer film obtained by laminating a transfer pattern layer on a substrate film is used as the decorating film, and when the decorating film is inserted between the molds, the transfer pattern layer side is set to the cavity space side. 2. The injection simultaneous painting method according to claim 1, wherein after the molded product is taken out from between the two molds, only the base film is peeled off from the molded product. 3. The heat distortion temperature of the painting film is T
_{When D1} [° C] is set, the painting film to be inserted between both molds is softened by heating to a temperature T _PRE (° C) where T _D1 ≤ T _PRE <T _M , and vacuum forming, pressure forming, or vacuum forming is performed. 2. The injection simultaneous painting method according to claim 1, wherein the painting film is preformed along the surface of the female mold by pressure molding, and then both molds are closed and the mold is clamped. 4. The heat distortion temperature [T _D1 ] of the painting film.
Is a value at ASTM-D-648, 18.6 kg / cm < ² >, The injection simultaneous painting method according to claim 3, wherein 5. The melting point (or melting temperature) T _M , the thermal conductivity κ, the thickness Δx, and the heat distortion temperature [T of the painting film.
_D1 ] is the melting point (or melting temperature) T _M , the thermal conductivity κ, and the thickness Δ of the base film that respectively constitutes the painting film.
5. The simultaneous injection painting method according to claim 1, wherein x and heat distortion temperature [T _D1 ] are 6. A film for simultaneous injection-molding, comprising a transfer film layer laminated on a base film, wherein the base film has a thermal conductivity κ [cal / sec.cm. ° C.] and a thickness Δx. [C
m], the melting point (or melting temperature) is T _M [° C.], and the temperature of the molten resin to be injected is T _N [° C.], T _N ≧ T _M , κ / Δx ≧ 3.0 × 10 ⁻² [ cal / sec.cm ²
℃], the film for simultaneous injection molding painting, which satisfies the condition of