JP2013082153A - Method of manufacturing resin molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a resin molded article that has excellent chemical resistance and can improve its yield.SOLUTION: The method of manufacturing a resin molded article 100 having a belt-like first surface 11, a second surface 12 and protruded parts 20, 21, and composed of a thermoplastic resin composition by an injection molding method includes steps of: charging the molten thermoplastic resin composition in a mold cavity; cooling the thermoplastic resin for a cooling time period of t1 at a cooling temperature T1 in a mold cavity to obtain a crude resin molded body; cooling the crude resin molded body in a liquid cooling medium for a cooling time period of t2 at a cooling temperature T2 to obtain a resin molded body; and drying the resin molded body to obtain the resin molded article, wherein the thermoplastic resin composition is composed of a combined resin composition including a polycarbonate resin, and a polyester resin or a styrene resin, and t1, T1, t2, T2 satisfy the conditions (1) of T1-T2=20-70°C, and (2) of t1<t2.

Description

  The present invention relates to a method for producing a resin molded product.

  Generally, handle parts are attached to building doors, train backs, rice cookers, etc. The handle parts are a belt-like first surface and a belt-like shape located on the back side of the first surface. It consists of a resin molded product which has a 2nd surface and the protrusion part which is provided in each of the both ends of a 2nd surface, and functions as an attaching part. Handle parts having such a shape are generally manufactured by an injection molding method. Specifically, the mold cavity is filled with a molten thermoplastic resin, cooled and solidified, and then taken out from the mold cavity. Obtained (for example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 10-193378

  However, the manufacturing method described in Patent Document 1 has room for improvement in terms of chemical resistance of the resin molded product obtained. Moreover, in the manufacturing method of patent document 1, the maximum sink amount may become large on the surface of the resin molded product obtained, and such a resin molded product is discarded. For this reason, the manufacturing method described in Patent Document 1 has room for improvement in terms of improving the yield of resin molded products.

  An object of this invention is to provide the manufacturing method of the resin molded product which can manufacture the resin molded product which has the outstanding chemical resistance, and can improve the yield of a resin molded product.

  As a result of intensive studies to solve the above problems, the present inventors first cooled the molten thermoplastic resin filled in the mold cavity, and then took out the resin molded product from the mold and removed the resin molded product. Further cooling was considered. However, this alone could not solve the above problem. Therefore, the present inventors have (A) a refrigerant used for cooling, (B) a cooling time t1 of the molten thermoplastic resin in the mold cavity, and a cooling time t2 of the resin molded product after being taken out from the mold. (C) the relationship between the cooling temperature T1 of the molten thermoplastic resin in the mold cavity and the cooling temperature T2 of the resin molded product after being taken out from the mold, and (D) the type of the molten thermoplastic resin Researched earnestly by focusing on. As a result, the present inventors use a liquid as a refrigerant, t1 and t2 have a specific relationship, T1 and T2 have a specific relationship, and a specific composite resin composition as a molten thermoplastic resin. The present inventors have found that the above problems can be solved when using a product, and have completed the present invention.

That is, the present invention has a first belt-like surface, a second belt-like surface located on the back side of the first surface, and a protrusion provided at each of both end portions of the second surface. A method for producing a resin molded article comprising a resin molded article comprising a composition using an injection molding method, the filling step filling the molten thermoplastic resin composition into a mold cavity, and the thermoplastic A first cooling step in which the resin composition is cooled in the mold cavity at a cooling time t1 and a cooling temperature T1 to obtain a crude resin molded body, and after completion of the first cooling step, the resin composition is taken out from the mold cavity. A second cooling step of cooling the crude resin molded body in a liquid refrigerant at a cooling time t2 and a cooling temperature T2 to obtain a resin molded body; and after completion of the second cooling step, the resin molding from the liquid refrigerant The body is taken out and dried to obtain the resin molded product The thermoplastic resin composition comprises a composite resin composition containing a polycarbonate resin and a polyester resin, or a composite resin composition containing a polycarbonate resin and a styrene resin, and cooling in the first cooling step In this method, the time t1, the cooling temperature T1, the cooling time t2 in the second cooling step, and the cooling temperature T2 satisfy the following conditions (1) and (2) simultaneously.
(1) T1-T2 = 20-70 [° C.]
(2) t1 <t2

  According to this production method, a resin molded product having excellent chemical resistance can be produced. In addition, since the maximum sink amount on the first surface and the second surface of the resin molded product can be sufficiently reduced, the yield of the resin molded product can also be improved.

In the method for producing a resin molded product, it is preferable that the cooling time t1 in the first cooling step and the cooling time t2 in the second cooling step further satisfy the following condition (3).
(3) t2 / t1 ≦ 10

  In this case, compared with the case where t2 / t1 exceeds 10, the productivity of the resin molded product is further improved.

  In the method for producing a resin molded product, it is preferable that a temperature of the liquid refrigerant in the second cooling step is 30 ° C. or less.

  In this case, compared with the case where the temperature of the liquid refrigerant in the second cooling step exceeds 30 ° C., the cooling effect is enhanced, and the maximum sink amount can be more sufficiently reduced.

  In the method for producing a resin molded article, the liquid refrigerant is caused to flow relative to the crude resin molded body, and the liquid refrigerant is caused to collide with the first surface of the coarse resin molded body. It is preferable to cool the crude resin molded body.

  In this case, sink marks are likely to occur on the first surface of the coarse resin molded body, and the maximum amount of sink marks tends to be large. By causing the liquid refrigerant to collide with the first surface of the coarse resin molded body, the first surface is It is possible to cool effectively, and it is possible to sufficiently reduce the maximum sink amount on the first surface.

  In the method for producing a resin molded product, it is preferable that the electric conductivity of the liquid refrigerant used in the second cooling step is 60 μS / cm or less.

  In this case, there is an advantage that foreign matters and pinholes on the surface of the resin molded product are less likely to be generated compared to the case where the electric conductivity of the liquid refrigerant exceeds 60 μS / cm.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the resin molded product which can manufacture the resin molded product which has the outstanding chemical resistance, and can improve the yield of a resin molded product is provided.

It is sectional drawing which shows an example of the resin molded product obtained with the manufacturing method of the resin molded product of this invention. It is sectional drawing which shows the metal mold | die of the injection molding apparatus used for the manufacturing method of the resin molded product of this invention. It is a figure which shows the filling process and 1st cooling process of the manufacturing method of the resin molded product of this invention. It is a figure which shows the 2nd cooling process of the manufacturing method of the resin molded product of this invention. It is a figure which shows the drying process of the manufacturing method of the resin molded product of this invention.

  Hereinafter, the present invention will be described in detail.

  First, a resin molded product manufactured by the manufacturing method of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing an example of a resin molded product manufactured by the manufacturing method of the present invention. As shown in FIG. 1, the resin molded product 100 includes a main body portion 10 having a belt-like first surface 11 and a belt-like second surface 12 positioned on the back side of the first surface 11, and both ends of the second surface 12. It has the protrusion parts 20 and 21 provided in each. The resin molded product 100 is composed of a composite resin composition containing a polycarbonate resin and a polyester resin, or a composite resin composition containing a polycarbonate resin and a styrene resin. Furthermore, in the resin molded product 100, a space 13 is formed inside the main body 10, a recess 20 a is formed in the protrusion 20, and the space 13 and the recess 20 a communicate with each other.

  Next, a method for manufacturing the resin molded product 100 will be described.

  First, before explaining the manufacturing method of the resin molded product 100, an injection molding apparatus for manufacturing the resin molded product 100 will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating an example of a mold of an injection molding apparatus that manufactures the resin molded product 100.

  As shown in FIG. 2, the injection molding apparatus includes a mold 40 and a heating cylinder device (not shown) for introducing a molten thermoplastic resin composition into the mold 40. The mold 40 includes a fixed mold part 41 and a movable mold part 42. When the fixed mold part 41 and the movable mold part 42 are joined, a mold cavity 43 and a liner 44 for introducing the molten thermoplastic resin composition into the mold cavity 43 are formed. . As shown in FIG. 2, the movable mold part 42 is provided with a pressurized fluid introduction part 46 including a cylinder 45 for introducing a pressurized fluid such as nitrogen gas.

  Next, the manufacturing method of the resin molded product 100 using the injection molding apparatus mentioned above is demonstrated using FIGS. 3-5 is a figure which shows a series of processes which manufacture the resin molded product 100, respectively.

  The resin molded product 100 is manufactured using an injection molding method, and specifically manufactured as follows.

  That is, as shown in FIG. 3, first, a molten thermoplastic resin composition is introduced into the liner 44 of the mold 40 from the heating cylinder device, and the molten thermoplastic resin composition R is filled into the mold cavity 43. (Filling step). At this time, the pressurized fluid is introduced into the molten thermoplastic resin composition R by the cylinder 45 of the pressurized fluid introducing portion 46 to form the space 13.

  Next, the molten thermoplastic resin composition R is cooled in the mold cavity 43 at a cooling time t1 and a cooling temperature T1, thereby obtaining a crude resin molded body 50 (first cooling step).

  After the first cooling step, as shown in FIG. 4, the crude resin molded body 50 taken out from the mold cavity 43 is cooled in the liquid refrigerant 60 at the cooling time t2 and the cooling temperature T2 to obtain a resin molded body. (Second cooling step).

  After the second cooling step, as shown in FIG. 5, the resin molded body 80 is taken out from the liquid refrigerant 60 and dried to obtain the resin molded product 100 (drying step).

Thus, when manufacturing the resin molded product 100, the cooling time t1 and the cooling temperature T1 in the first cooling step and the cooling time t2 and the cooling temperature T2 in the second cooling step satisfy the following conditions (1) and (2) at the same time. Try to meet.
(1) T1-T2 = 20-70 [° C.]
(2) t1 <t2

  By manufacturing the resin molded product 100 as described above, the resin molded product 100 having excellent chemical resistance can be manufactured. In addition, since it is possible to sufficiently reduce the maximum sink amount of the first surface 11 and the second surface 12 of the resin molded product 100, the yield of the resin molded product 100 can be improved.

  Hereinafter, each of the filling step, the first cooling step, and the second cooling step will be described in detail.

(Filling process)
As the thermoplastic resin composition R, a composite resin composition containing a polycarbonate resin and a polyester resin, or a composite resin composition containing a polycarbonate resin and a styrene resin is used. When a resin composition containing only a polycarbonate resin is used as the resin, the chemical resistance of the resin molded product 100 is lowered.

  Examples of the polycarbonate resin include aromatic polycarbonate and aliphatic polycarbonate.

  Examples of the polyester resin include polyethylene terephthalate resin and polybutylene terephthalate resin.

  The styrene resin may be a resin having a structural unit derived from styrene. For this reason, as the styrene resin, for example, ABS resin, AES resin, and AS resin can be used in addition to polystyrene resin.

  If necessary, the composite resin composition may be blended with at least one selected from the group consisting of a rubbery polymer, a heat stabilizer, and a colorant.

  Examples of rubber polymers include core / shell type graft copolymers composed of polybutadiene / polystyrene copolymer (core) / alkyl acrylate / alkyl methacrylate copolymer (shell), and polybutadiene (core) / alkyl acrylate. A core / shell type graft copolymer made of an alkyl methacrylate copolymer (shell) can be used.

  Examples of the heat stabilizer include tris (2,4-di-tert-butylphenyl) phosphite and pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. Can be mentioned.

  Examples of the colorant include carbon black.

  In addition, the composite resin composition includes, as necessary, a plasticizer, an antioxidant, an ultraviolet absorber, an organic nickel compound, an ultraviolet stabilizer, an antistatic agent, a flame retardant, an antifungal agent, a lubricant, an organic foaming agent, At least one selected from the group consisting of a transparent nucleating agent, a crosslinking agent, and an impact resistance strengthening agent may be further blended.

(First cooling step)
The first cooling step is a step of cooling the molten thermoplastic resin composition R in the mold cavity 43 at a cooling time t1 and a cooling temperature T1, and the first cooling step is a molten thermoplastic resin composition R. And a pressure holding state after filling.

  Accordingly, the cooling time t1 refers to the time from when the molten thermoplastic resin composition R is filled to when the crude resin molded body 50 is taken out after the pressure is maintained.

  The cooling time t1 is preferably 30 to 60 seconds, and more preferably 35 to 50 seconds. When the cooling time t1 is within the above range, the thermoplastic resin composition R is more sufficiently cooled than when the cooling time t1 is less than 30 seconds, and compared with the case where the cooling time t1 exceeds 60 seconds. Further, the productivity of the resin molded product 100 can be improved.

  In the cooling time t1, the proportion of the time required for the pressure holding state (hereinafter referred to as “pressure holding time”) is preferably 30 to 90%, more preferably 40 to 80%. . When the ratio of the pressure holding time to the cooling time t1 is in the range of 30 to 90%, sink marks and burrs are reduced as compared with a case where the ratio is out of the range.

  Further, the cooling temperature T1 refers to the set temperature of the mold 40, not the actually measured temperature of the molten thermoplastic resin composition R.

  The cooling temperature T1 is preferably 40 to 100 ° C, more preferably 50 to 90 ° C.

(Second cooling step)
In the second cooling step, after the first cooling step, the crude resin molded body 50 taken out from the mold cavity 41 is cooled in the liquid refrigerant 60 at the cooling time t2 and the cooling temperature T2 to obtain a resin molded body. It is.

  The liquid refrigerant 60 may be a liquid that can function as a refrigerant and does not dissolve the crude resin molded body 50. Here, the reason why the liquid is used as the coolant for cooling the crude resin molded body 50 is that the maximum sink amount cannot be sufficiently reduced with a gas such as air. Examples of the liquid refrigerant 60 include water and water to which a small amount of alcohol is added. Of these, water is preferred.

  The electric conductivity of the liquid refrigerant 60 is preferably 60 μS / cm or less, and more preferably 40 μS / cm or less. When the electric conductivity of the liquid refrigerant is 60 μS / cm or less, there are fewer foreign matters and pinholes on the surface of the resin molded product than when the electric conductivity exceeds 60 μS / cm.

  The liquid refrigerant 60 may or may not flow relatively with respect to the crude resin molded body 50, but is preferably flowed relatively. In this case, the heat from the coarse resin molded body 50 does not remain in the vicinity of the coarse resin molded body 50, and the coarse resin molded body 50 can be effectively cooled. When the liquid refrigerant 60 is caused to flow, the flow of the liquid refrigerant 60 is preferably caused to collide with the first surface 11 of the crude resin molded body 50. This is because sinking is likely to occur on the first surface 11, so that the first surface 11 is effectively cooled by colliding the flow of the liquid refrigerant 60, and the maximum sinking amount is sufficiently reduced. At this time, it is preferable that the flow direction of the liquid refrigerant 60 and the first surface 11 of the coarse resin molded body 50 are substantially perpendicular. In this case, there is an advantage that the amount of sink on the first surface 11 can be reduced.

  In order to cause the liquid refrigerant 60 to flow relative to the crude resin molded body 50, the container 70 is usually prepared, and the liquid refrigerant 60 is discharged from the container 70 at the same time as the liquid refrigerant 60 is supplied to the container 70. That's fine. At this time, when the discharged liquid refrigerant 60 is radiated, the discharged liquid refrigerant 60 may be supplied to the container 70 and circulated. Alternatively, the crude resin molded body 50 may be moved without circulating the liquid refrigerant 60.

  At this time, the relative flow rate of the liquid refrigerant 60 with respect to the crude resin molded body 50 is not particularly limited, but is preferably 10 cm / s or less, and more preferably 5 cm / s or less, for reasons of cooling efficiency. preferable.

  Here, the cooling time t2 refers to the time from when the crude resin molded body 50 is immersed in the liquid refrigerant 60 to when it is taken out.

  The cooling time t2 may be longer than the cooling time t1. This is because, when the cooling time t2 is equal to or less than the cooling time t1, the maximum sink amount increases and the yield of the resin molded product 100 decreases.

However, t2 is the following formula:
(3) t2 / t1 ≦ 10
Is preferably satisfied. In this case, compared with the case where t2 / t1 exceeds 10, the productivity of the resin molded product is further improved.

  t2 / t1 is preferably 8 or less, more preferably 6 or less.

  The cooling temperature T2 refers to the set temperature of the liquid refrigerant 60, not the actual temperature of the liquid refrigerant 60.

  The cooling temperature T2 should just satisfy | fill (T1-T2) = 20-70 degreeC. When (T1-T2) is less than 20 ° C., the chemical resistance of the resin molded product 100 is lowered. On the other hand, when (T1-T2) exceeds 70 ° C., the amount of sink marks increases.

  At this time, the temperature of the liquid refrigerant 60, that is, the cooling temperature T2, is preferably 30 ° C. or less, and more preferably 20 ° C. or less. In this case, compared with the case where the temperature of the liquid refrigerant 60 in the second cooling step exceeds 30 ° C., the cooling effect is enhanced, and the maximum sink amount can be more sufficiently reduced. However, the temperature of the liquid refrigerant 60 is higher than the freezing point of the refrigerant 60. When the temperature of the refrigerant 60 is set to a temperature equal to or lower than the freezing point, the refrigerant 60 becomes solid, and the crude resin molded body 50 cannot be immersed in the refrigerant 60.

(Drying process)
The drying step is a step of obtaining the resin molded product 100 by taking out the resin molded body 80 from the liquid refrigerant 60 and drying it after the second cooling step. Drying is performed to remove the liquid refrigerant 60 adhering to the surface of the resin molded body 80. The drying condition depends on the type of the liquid refrigerant 60 and cannot be generally specified. For example, when the liquid refrigerant 60 is water, the resin molded body 80 is left in an environment of 15 to 30 ° C. for about 5 to 10 minutes. That's fine. Alternatively, compressed air can be blown onto the resin molded body 80 to remove moisture, or moisture can be wiped off with a flexible cloth or the like.

  The resin molded product 100 can be used as, for example, a handle of a rice cooker, a handle provided on the backrest of a train seat, a door handle of an automobile, a handle for opening and closing a door of a window or an entrance.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the space 13 is formed inside the main body 10 of the resin molded product 100, but the space 13 may not be formed inside the main body 10. That is, the resin molded product 100 may be solid rather than hollow. In this case, the pressurized fluid introduction part 46 is omitted from the movable mold part 42 of the mold 40. The recess 20a is not necessarily required and can be omitted.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example.

The raw materials of the resin composition used in the examples and comparative examples are as follows.
Polycarbonate resin 1) Aromatic polycarbonate resin (hereinafter “PC-A”):
Iupilon (registered trademark) E-2000 manufactured by Mitsubishi Engineering Plastics Co., Ltd.
Viscosity average molecular weight 28,000
2) Aromatic polycarbonate resin (hereinafter “PC-B”):
Iupilon (registered trademark) S-3000 manufactured by Mitsubishi Engineering Plastics Co., Ltd.
Viscosity average molecular weight 22,000
Polyethylene terephthalate resin PET “Novapex GG900D” manufactured by Mitsubishi Chemical Corporation (using germanium dioxide catalyst, germanium atom content 28 ppm, intrinsic viscosity 1.10 dL / g)
Polybutylene terephthalate resin <br/> PBT manufactured by Mitsubishi Engineering Plastics
NOVADURAN (registered trademark) 5020 Intrinsic viscosity 1.20 dl / g, hereinafter “PBT-1”
ABS resin <Santac UT-61> manufactured by Japan A & L Co., Ltd.
Rubber polymer 1) “Paraloid KCZ201N” manufactured by Rohm and Haas Japan, a core made of polybutadiene / polystyrene copolymer (core) / alkyl acrylate / alkyl methacrylate copolymer (shell) / Shell type graft copolymer, hereinafter "Rubber polymer-1"
2) “EXL2603” manufactured by Rohm and Haas Japan, a core / shell type graft copolymer comprising polybutadiene (core) / alkyl acrylate / alkyl methacrylate copolymer (shell), hereinafter referred to as “rubber polymer” -2 "
Heat Stabilizer 1) “Adeka Stub AS2112” (Tris (2,4-di-tert-butylphenyl) phosphite) manufactured by Asahi Denka Kogyo Co., Ltd., hereinafter “Heat Stabilizer-1”
2) “Irganox 1010” manufactured by Ciba Specialty Chemicals
Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4
-Hydroxyphenyl) propionate], hereinafter "thermal stabilizer-2"
Carbon black <br/> Oil furnace carbon black "# 1000" manufactured by Mitsubishi Chemical Corporation

<Preparation of resin compositions-1, 2, 3, 4 and 5>
Using the above raw material components, five types of polycarbonate resin compositions (compositions 1 to 5) contained in the proportions shown in Table 1 below were prepared as follows. That is, after each component shown in Table 1 was uniformly mixed with a tumbler-mixer at a ratio shown in the same table, it was fed to a twin-screw extruder (“TEX30XCT” manufactured by Nippon Steel Works) and heated to 240 to 280 ° C. The melt-kneaded resin composition was quenched in a water bath and pelletized using a pelletizer to obtain resin composition pellets.

(Examples 1-5 and Comparative Examples 1-3)
After the resin composition 1 is dried at 120 ° C. for 4 hours or more, a J-220EV-P type injection molding machine manufactured by Nippon Steel Works has a handshake part at the center and attachment parts to the vehicle body at both ends. An outer handle molding die was attached. Thereafter, the resin composition 1 melted in the cylinder was filled into the mold cavity through the mold liner. At this time, the cylinder temperature was 260 ° C., the mold temperature was 30 to 120 ° C., and the filling time was 10 seconds.

  Thereafter, the molten resin composition was cooled while holding at a holding pressure of 50 MPa to obtain a crude resin molded product having a cross-sectional shape (longitudinal cross-section) shown in FIG. At this time, the cooling time t1 and the cooling temperature T1 were as shown in Table 2.

  Next, this crude resin molded body was taken out from the mold. At this time, the molding cycle time Tt was as shown in Table 2.

  Thereafter, the crude resin molded body was fixed to a jig and cooled by being immersed in a refrigerant in a container equipped with a chiller. At this time, the coolant was water, and the cooling time t2, the cooling temperature T2 (refrigerant temperature), and the electrical conductivity of the coolant were as shown in Table 2. At this time, the relative flow rate of water with respect to the first surface of the crude resin molded body in the container (water tank) was set as shown in Table 2. Thus, a resin molded body was obtained.

  Next, the resin molded body obtained as described above was taken out of the refrigerant and dried at 25 ° C. for 5 minutes. Thus, an outer handle molded product which is a resin molded product was obtained.

(Comparative Example 4)
The resin composition 5 was dried at 120 ° C. for 4 hours or more. Thereafter, the cooling temperature T1, the cooling time t1, the cooling temperature T2 (refrigerant temperature), the cooling time t2, the electric conductivity of the refrigerant, the relative flow velocity, (T1-T2) and t2 / t1 are as shown in Table 2. An outer handle molded article was manufactured in the same manner as in Example 1 except that.

(Examples 6 to 10 and Comparative Examples 5 to 7)
The resin composition 2 was dried at 100 ° C. for 4 hours or more. Thereafter, the cooling temperature T1, the cooling time t1, the cooling temperature T2 (refrigerant temperature), the cooling time t2, the electric conductivity of the refrigerant, the relative flow velocity, (T1-T2) and t2 / t1 are as shown in Table 3. An outer handle molded article was manufactured in the same manner as in Example 1 except that.

(Examples 11 to 15 and Comparative Examples 8 to 10)
The resin composition 3 was dried at 120 ° C. for 4 hours or more. Thereafter, the cooling temperature T1, the cooling time t1, the cooling temperature T2 (refrigerant temperature), the cooling time t2, the electric conductivity of the refrigerant, the relative flow velocity, (T1-T2) and t2 / t1 are as shown in Table 4. An outer handle molded article was manufactured in the same manner as in Example 1 except that.

(Comparative Examples 11-14)
The resin composition 4 was dried at 120 ° C. for 4 hours or more. Thereafter, the cooling temperature T1, the cooling time t1, the cooling temperature T2 (refrigerant temperature), the cooling time t2, the electric conductivity of the refrigerant, the relative flow velocity, (T1-T2) and t2 / t1 are as shown in Table 5. An outer handle molded article was manufactured in the same manner as in Example 1 except that.

  With respect to the outer handle molded products obtained in Examples 1 to 15 and Comparative Examples 1 to 14, the maximum sink amount, glossiness and pinhole were measured, and the chemical resistance was examined.

(1) Maximum sink amount About the outer handle molded product obtained in Examples 1-15 and Comparative Examples 1-14, the surface between one end and the other end of the mounting portion of the vehicle body (first 2), the maximum amount of sink marks was measured with a surface roughness meter (trade name: Surfcom 3000A) manufactured by Tokyo Seimitsu Co., Ltd. The results are shown in Tables 2-5. In Tables 2 to 5, three outer handle molded articles were prepared for each example and each comparative example, and the average value of the maximum sink amount measured for these three outer handle molded articles was defined as the maximum sink amount. . The acceptance criteria for the maximum sink amount was 4.5 μm or less, and it was rejected when it exceeded 4.5 μm. Here, “4.5 μm” means a value that determines whether or not to dispose of the outer handle molded product.

(2) Glossiness (gross)
About the outer handle molded product obtained in Examples 1-15 and Comparative Examples 1-14, the glossiness of the handshake part of the center part was measured according to the method of JISZ8741. The results are shown in Tables 2-5. Note that VG-2000 (trade name) manufactured by Nippon Denshoku Co., Ltd. was used as the measuring machine, and the measurement angle was 60 degrees. In Tables 2 to 5, three outer handle molded articles were prepared for each example and each comparative example, and the average gloss value measured for these three outer handle molded articles was defined as the glossiness. The larger the measured value, the closer to the mirror state.

(3) Pinhole About the outer handle molded product obtained in Examples 1-15 and Comparative Examples 1-14, the number of pinholes was counted. The results are shown in Tables 2-5.

(4) Chemical resistance test The outer handle molded products obtained in Examples 1 to 15 and Comparative Examples 1 to 14 were immersed in commercial gasoline for 7 hours, and the presence or absence of surface cracks was observed. The state of surface cracks was evaluated in the following four stages.
A: No crack or whitening on the surface is observed B: Slight cracking or whitening is observed on the surface C: Cracks or whitening on the surface is recognized D: Results of remarkable cracking or whitening on the surface are shown in Tables 2 to 5 . In addition, about chemical resistance, if it was A, it was set as the pass, and if it was BD, it was set as the failure.

  From the results shown in Tables 2 to 5, it was found that the outer handle molded products obtained in Examples 1 to 15 satisfied the acceptance criteria for both the maximum sink amount and chemical resistance. On the other hand, it was found that the outer handle molded products obtained in Comparative Examples 1 to 14 did not reach the acceptance standard for at least one of the maximum sink amount and chemical resistance.

  Therefore, according to the manufacturing method of the resin molded product of this invention, it was confirmed that the resin molded product which has the outstanding chemical resistance can be manufactured, and the yield of the resin molded product can be improved.

DESCRIPTION OF SYMBOLS 11 ... 1st surface 12 ... 2nd surface 20,21 ... Projection part 43 ... Mold cavity 50 ... Coarse resin molding 60 ... Liquid refrigerant 70 ... Container 80 ... Resin molding 100 ... Resin molding R ... Thermoplastic resin composition object

Claims (5)

A resin made of a thermoplastic resin composition, having a belt-like first surface, a belt-like second surface located on the back side of the first surface, and protrusions provided at both ends of the second surface. A method for producing a resin molded product, wherein a molded product is manufactured using an injection molding method,
A filling step of filling the molten thermoplastic resin composition in the mold cavity;
A first cooling step of cooling the thermoplastic resin composition in the mold cavity at a cooling time t1, a cooling temperature T1 to obtain a crude resin molded body,
A second cooling step of obtaining the resin molded body by cooling the crude resin molded body taken out from the mold cavity in a liquid refrigerant at a cooling time t2 and a cooling temperature T2 after the completion of the first cooling step;
After the second cooling step, the resin molded body is taken out from the liquid refrigerant and dried to obtain the resin molded product,
The thermoplastic resin composition is composed of a composite resin composition containing polycarbonate and polyester, or a composite resin composition containing polycarbonate and a styrenic resin,
A method for producing a resin molded product, wherein the cooling time t1 and the cooling temperature T1 in the first cooling step and the cooling time t2 and the cooling temperature T2 in the second cooling step satisfy the following conditions (1) and (2) simultaneously.
(1) T1-T2 = 20-70 [° C.]
(2) t1 <t2 The method for producing a resin molded product according to claim 1, wherein the cooling time t1 in the first cooling step and the cooling time t2 in the second cooling step further satisfy the following condition (3).
(3) t2 / t1 ≦ 10   The method for producing a resin molded product according to claim 1 or 2, wherein the temperature of the liquid refrigerant in the second cooling step is 30 ° C or lower.   In the second cooling step, the liquid refrigerant is caused to flow relative to the crude resin molded body, and the liquid refrigerant is caused to collide with the first surface of the coarse resin molded body, thereby forming the crude resin molding. The manufacturing method of the resin molded product as described in any one of Claims 1-3 which cools a body.   The method for producing a resin molded product according to any one of claims 1 to 4, wherein the liquid refrigerant used in the second cooling step has an electric conductivity of 60 µS / cm or less.

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