CN1127491A - Low-pressure injection molding method - Google Patents
Low-pressure injection molding method Download PDFInfo
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- CN1127491A CN1127491A CN94190340.0A CN94190340A CN1127491A CN 1127491 A CN1127491 A CN 1127491A CN 94190340 A CN94190340 A CN 94190340A CN 1127491 A CN1127491 A CN 1127491A
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- synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/26—Moulds
- B29C45/37—Mould cavity walls, i.e. the inner surface forming the mould cavity, e.g. linings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/1703—Introducing an auxiliary fluid into the mould
- B29C45/1704—Introducing an auxiliary fluid into the mould the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles
- B29C2045/1717—Temperature controlled mould parts to control the location or configuration of the hollow
Abstract
The present invention discloses a low-pressure plastic injection method for synthetic resin. Wherein the utilized mould uses a heat-proof resin layer with the thickness of 0.1mm to 0.5mm covering the wall of a metal mould cavity, and the resin injection molding is composed at the low flowing speed of partially no more than 100mm/s. The method can produce molding products that has the improved gloss, the dent and slowly moving moulage, and that has good appearance and excellent stress cracking resistance (SCR) performance.
Description
The present invention relates to the low-pressure injection molding method of synthetic resin.
More particularly, the present invention relates to a kind of low-pressure injection molding method of synthetic resin, wherein, the mould that uses covers the die cavity wall of metal die (mold proper) itself with the heat-resistant resin of one deck specific thicknesses scope, and, carry out injection moulding at least partially under the low flow velocity synthetic resin being injected die cavity.
As the injection moulding process of synthetic resin, extensively adopt injection pressure or the low low-pressure injection molding method of mold clamping force in the practical application.
Low-pressure injection molding method comprises:
Plastics Technology, April, 44 (1994) or the auxiliary injection moulding process of gas introduced of U.S. Patent No. 4,101,617.In this method, at first synthetic resin is injected die cavity, and then in die cavity injecting gas, fall by means of the low pressure of gas, the injection pressure of gas is transferred to the flow process end of synthetic resin equably, thereby carries out low-pressure injection molding.
The inventor discloses auxiliary injection moulding process or the auxiliary injection moulding process of liquid of oligomer in European patent No.0599009A1, they are low-pressure injection molding methods similar to aforesaid way.
BP No.1 for example, the method that 156,217 disclosed sandwich injection moulding process are members of a kind of moulding sandwich structure wherein, is at first injected a kind of synthetic resin, injects another kind of synthetic resin then, is full of die cavity.When use contains the synthetic resin of blowing agent,, can carry out low-pressure injection molding by means of the foaming power of core resin.
In addition, extensively adopt a kind of injection-compression-molding method recently, wherein, synthetic resin is injected the mould that the matched moulds plate retreats slightly, make die cavity thicker (heavy wall), make die cavity return to preset thickness (thickness of wall) by the matched moulds plate is advanced then, under low pressure make synthetic resin be full of whole die cavity.
A Synthetic Resin, Vol.37, No.9, Page 34 (1991), wait to disclose the Hettinga low-pressure injection molding method, wherein adopt extremely low injection pressure and extremely low speed, adopt this method more favourable according to the shape of moulded products.
Compare with conventional injection moulding process, the advantage of these low-pressure injection molding methods is to use the low pressure filled synthetic resin, but its shortcoming is the flow velocity step-down of synthetic resin in die cavity.When the flow velocity of synthetic resin was low in the die cavity, the surface of injection moulded products was poor to the repeatability of die face, becomes coarse, and the stress crack resistance performance of goods (this paper brief note is " SCR ") variation.Therefore, need to improve these methods.
In the traditional injection moulding forming method, improve repeatability and the solvent resistance of goods to die face by changing condition of molding in every way.The condition that has the greatest impact is a mold temperature, and mold temperature risen near the softening temperature of synthetic resin can obtain effect preferably.But, during the rising mold temperature, cooling and to solidify the required time of plasticized resin elongated.Thereby lower shaping efficiency.Therefore need a kind of mold temperature that need not improve just can improve reproducible method, even the method that perhaps rising mold temperature also can not prolong cool time to die face.As the example of a kind of method in back, a method is the hole that is provided for heating and cooling on mould respectively, heat medium and cooling agent is alternately flowed, with mould heating and cooling repeatedly.But the shortcoming of this method is the heat consumption height, and cool time is long.
The inventor discloses a kind of method at the open No.93/06980 of WO, and it is used for improving the repeatability to die face with the mould wall of the little material covering die cavity of thermal conductivity when conventional injection moulding.
But, almost do not see the report of correlation between the surface condition of thickness, various condition of molding and injection moulded products of the thermal insulation layer that covers on the research mould wall.
In injection moulding process, liquid that the low-pressure injection molding method such as the gas of common employing are at present assisted auxiliary injection moulding process, oligomer auxiliary injection moulding process, injection-compression-molding method, sandwich injection molding forming method and Hettinga low-pressure injection molding method, the flow velocity of synthetic resin in die cavity is low, and the flow velocity of resin often changes suddenly in its flow process.Because the flow velocity of resin is low, and is poor to the repeatability of die face, and, form the current mark that is known as slow-action impression (hesitation mark), make degraded appearance in flow velocity variation place suddenly of resin.In addition, when the flow velocity of synthetic resin in die cavity hangs down, the resin bed thickening of curing, thereby usually make SCR (stress crack resistance performance) variation.Therefore, require to improve the outward appearance and the SCR of goods.The present invention has reached above-mentioned purpose.
The inventor studied low flow velocity, the injection moulding of resin in low-pressure injection molding method low-pressure, be coated with the relation between the metal die etc. of thermal insulation layer, also further studied the relation between the outward appearance, SCR etc. of injection-molded item, thereby finished the present invention.
Promptly, the present invention relates to the low-pressure injection molding method of synthetic resin, wherein, the mould that uses with a layer thickness greater than 0.1mm and be not more than the die cavity wall of the heat stable resin covering metal die of 0.5mm itself, and, carry out injection moulding at least partially under the low flow velocity that is not higher than 100mm/s synthetic resin being injected die cavity.
The invention still further relates to above-mentioned injection moulding process, contain the resin reinforcing material in the synthetic resin wherein, the moulded products that this resin of injection moulding makes does not have the resin reinforcing material to stretch out product surface basically.
The invention still further relates to above-mentioned injection moulding process, the resin reinforcing material that wherein contains in the synthetic resin is the synthetic resin that a kind of rubber strengthens.
The invention still further relates to above-mentioned injection moulding process, the synthetic resin that wherein said rubber strengthens is the phenylethylene resin series that rubber strengthens.
In addition, the invention still further relates to above-mentioned injection moulding process, the thickness of heat-resistant resin layer is in the scope of 0.15mm-0.45mm in the base.
In addition, the invention still further relates to above-mentioned injection moulding process, wherein, described low-pressure injection molding method is at least a injection moulding that is selected from following method: the injection moulding process that gas is auxiliary, the injection moulding process that liquid is auxiliary, the injection moulding process that oligomer is auxiliary, injection compression molding method, core resin is the sandwich injection moulding process of Foamex, and the Hettinga low-pressure injection molding method.
Figure 1A, 1B and 1C represent the low-pressure injection molding method (injection moulding process that gas is auxiliary, the injection moulding process that oligomer is auxiliary, the injection moulding process that liquid is auxiliary etc.) that the present invention adopts.
Fig. 2 represents the viscosity of various synthetic resin and fluid and the relation of temperature.
Fig. 3 A and 3B represent another example that the auxiliary injection moulding process of using gases carries out moulding.
Fig. 4 A and 4B represent the method for injection compression molding in the low-pressure injection molding method that the present invention adopts.
Fig. 5,6,7 and 8 to be illustrated in the mould self-temperature be the temperature of the polystyrene that strengthens of 50 ℃, rubber when being 240 ℃ of following injection mo(u)ldings, near the temperature distribution history (calculated value) the mould wall.
Fig. 9 represents the flow graph of synthetic resin in die cavity.
Figure 10 represents the heat (calculated value) that the mobile shearing of synthetic resin in die cavity produces.
Figure 11 A and 11B represent to adopt the metal die of thermal insulation layer covering, even also can improve SCR (stress crack resistance performance) under the low speed injection moulding.
Figure 12 is illustrated in the injection moulding process of synthetic resin, impose on the die wall resin pressure over time.
Figure 13 represents the method for a kind of SCR of measurement.
Figure 14 A represents the relation of the gloss and the flow velocity of synthetic resin in die cavity of moulded products; Figure 14 B represents the relation of the thickness of the gloss of moulded products and polyimide resin thermal insulation layer.
Figure 15 A and 15B represent the cross section schematic diagram of injection moulded products near surface.
The meaning of symbol among the figure:
1. mould itself
2. die cavity
3. synthetic resin
4. change in flow point
5. gas
6. moulded products
7. moulded products
8. cast gate
9. flow process end
10. thick wall part
11. gas passage
12. mould
13. cured layer
The front 14. flow
15. point to flowing of die wall
16. the flow velocity of synthetic resin
17. the center of die cavity
18. velocity flow profile curve
19. the distribution curve of shear rate
20. the cured layer of superficial layer
21. core
22. the concave side of moulded products
23. the convex side of moulded products
24. replace the point of resin with gas
25. sample
26. apply the point of bending stress
27. load
28. rubber grain
29. moulded products
The synthetic resin that is used for the present invention is thermoplastic resin general in the injection mo(u)lding, for example has: polyolefin, such as polyethylene, polypropylene etc.; Phenylethylene resin series is such as polystyrene of polystyrene, styrene-acrylonitrile copolymer, rubber reinforcement etc.; Polyamide, polyester, Merlon, methacrylic resin, the vinyl chloride resin, etc. Synthetic resin preferably contains 1%-60% resin reinforcing material. Reinforcing material for example is various rubber, various fibers such as glass fibre, carbon fiber etc., and inorganic filler such as talcum, calcium carbonate, kaolin etc., etc. The synthetic resin that uses is preferably the synthetic resin of rubber reinforcement, and what at first preferably use is the phenylethylene resin series of rubber reinforcement.
The phenylethylene resin series that is used for the present invention's rubber reinforcement comprises the polystyrene of rubber reinforcement, ABS resin, and AAS resin, MBS resin etc., wherein rubber phase such as island General Decentralized are in resin-phase. The polystyrene of rubber reinforcement be wherein such as the rubber phase of polybutadiene, SBR etc. such as island General Decentralized in mainly containing the resin of cinnamic fluoropolymer resin in mutually. ABS resin be wherein such as the rubber phase of polybutadiene, SBR etc. such as island General Decentralized in the resin of the copolymer resin that mainly contains styrene and acrylonitrile in mutually. AAS resin be wherein such as the rubber phase of acrylic rubber such as island General Decentralized in the resin of the copolymer resin that mainly contains styrene and acrylonitrile in mutually, the MBS resin be wherein rubber phase such as island General Decentralized in the resin of the copolymer resin that mainly contains styrene and methacrylonitrile in mutually.
In addition, the present invention also can use the blend that mainly contains a kind of above-mentioned resin. For example, can use the polystyrene resin of rubber reinforcement and the blend of polyphenylene oxide. The injection moulded products of these resins of the inventive method preparation they performance and cost between fabulous balance is arranged, thereby should be used as the cover of photoelectricity utensil and electrical equipment, all kinds of commodity and various industrial part.
The metal die that " mould itself " of the present invention definition commonly used when meaning shaping synthetic resin, it by such as iron or mainly contain the ferrous materials, aluminium of iron, aluminium alloy, kirsite or the beryllium-copper alloys etc. that mainly contain aluminium make. Particularly preferably use the metal die of being made by ferrous materials.
The heat stable resin that is used as thermal insulation layer among the present invention is that glass transition temperature is not less than 140 ℃, preferably is not less than 160 ℃ and/or fusing point and is not less than 230 ℃, preferably is not less than 250 ℃ heat stable resin.
In 0.0001 to 0.002cal/cms ℃ scope, with the Metal Phase ratio, its thermal conductivity is very little usually for the thermal conductivity of heat stable resin of the present invention. This heat stable resin preferably tensile fracture elongation is not less than 5%, preferably is not less than 10%, more preferably is not less than 15% toughened resin. Tensile fracture elongation is measured according to ASTM D638, and rate of extension is 5mm/ minute when measuring.
According to the present invention, the heat stable resin that is suitable for use as thermal insulation layer is the heat-resistant polymer that has aromatic ring in its main chain, such as dissolving in the various noncrystalline heat-resistant polymer of organic solvent, various polyimides etc.
Noncrystalline heat-resistant polymer for example has polysulfones, polyether sulfone, polyarylsufone, poly-aryl compound, polyphenylene oxide etc.
Polyimides comprises various polyimides, preferably uses high-molecular linear polyimides and partial cross-linked polyimides.Usually since the high-molecular linear polyimides have high tensile fracture elongation, toughness and excellent durability and preferably used.For example, the preferred high-molecular linear polyimides that uses with repetitive shown in the table 1.
In the present invention, the thermal coefficient of expansion of heat-resistant resin layer is approaching with mould itself more, preferred more use.Usually in the injection mo(u)lding of synthetic resin, therefore heating and cooling repeatedly when moulding, when the difference of thermal expansion coefficients of heat-resistant resin layer and mould itself is very big, produce stress.Even before injection mo(u)lding, when covering mould itself, when carrying out heating and cooling, produce stress between the two with heat-resistant resin layer.When stress surpassed a certain particular value, heat-resistant resin layer and mould itself were peeled off.Table 2 has provided the thermal coefficient of expansion of the polyimides with low hot expansibility.Should use various polyimides with low thermal coefficient of expansion.
In table 2, when " free (Free) " expression imidizate polyimide precursor prepares polyimide film, but free shrink during film forming, and " Bifix " expression is fixed on film in the rectangular frame, suppress the contraction that imidizate causes, thereby make polymer chain because stress planar is orientated.With the solution coat of polyimide precursor in the Coefficient of Thermal Expansion value of the polyimides that adds thermosetting on the mould between " Free " and " Bifix ".The repetitive of table 1 polymer
R:R
1And R
2 
The thermal coefficient of expansion (10 of the polyimides of table 2 low-thermal-expansion performance
-5k
-1)
Generally speaking, in one-shot forming, can make the injection mo(u)lding economically valuable of complex-shaped moulded products.In order to cover the surface of complicated die with heat stable resin, make resin and mould secure bond, most preferably at first be coated with the solution of the precursor of the solution of heat-resistant polymer and/or heat-resistant polymer, add the thermosetting heat-resistant polymer then.Therefore, the precursor of heat-resistant polymer among the present invention or heat-resistant polymer preferably dissolves in the solvent.
As other example of heat stable resin, can also mode same as described above use to have the flexile epoxy resin, siloxane resin, melamine resinoid.Especially, can use to have flexible modified epoxy, for example use the modified epoxy of toughened resin modification.
According to the present invention, requiring will height as the heat stable resin of thermal insulation layer and the cohesive force between the mould itself, and it is wide at room temperature to be not less than 0.5kg/10mm, and it is wide preferably to be not less than 0.8kg/10mm, and it is wide more preferably to be not less than 1kg/10mm.Cohesive force described here is that it is wide that the thermal insulation layer that bonds is cut into 10mm, draws perpendicular to the direction of adhesive surface on the speed edge of 20mm/min then, makes resin bed peel off required power.Peeling force can not and be measured number of times with measurement point and change.Importantly the minimum of a value of peeling force wants high, and preferred peeling force is constant in higher value.The above-mentioned cohesive force value of the present invention is the minimum cohesive force value in the main region of mould.
As another embodiment, as needs, can cover again a layer thickness be lower than the heat stable resin layer thickness about 1/5, preferably be lower than 1/10 another kind of material, further improve smoothness, further improve the anti-damage performance on surface or improve release property as the heat stable resin thin layer surface of thermal insulation layer.For example, can be coated with the coating that is used to improve anti-damage performance on the surface of synthetic resin layer, it is commonly referred to as hard conating.It is exemplified as heat-curable silicone class hard coat material, particularly the type siloxane hard coat material is mixed obtaining hard coat material with epoxy compounds, and it has excellent bond performance, is optimized among the present invention.In order to improve release property, can fluorine resin coating or type siloxane polymer.In addition, as needs, can on as the heat-resistant resin layer of thermal insulation layer, cover the skim metal.For example, can on thermal insulation layer, cover chromium layer or nickel dam etc.When using thin metal layer, metal layer thickness preferably is not more than 1/10 of heat stable resin layer thickness.
Suitably control is as the thickness of the heat-resistant resin layer of thermal insulation layer, makes it greater than 0.1mm and be not more than in the scope of 0.5mm, preferably is being not less than 0.15mm and is being not more than in the scope of 0.45mm.In low-pressure injection molding method of the present invention, when the thickness of thermal insulation layer is not more than 0.1mm, can not show enough effect of heat insulation.In other words, by the flow velocity of further investigation synthetic resin in die cavity, as the thickness of the heat-resistant resin layer of thermal insulation layer and moulding article to the relation between this three of repeatability of die face, finished the present invention, thereby find, the thermal insulation layer thickness and the flow velocity of synthetic resin in die cavity that require are in close relations, when the flow velocity of synthetic resin in die cavity was not more than 100mm/s, the thickness of thermal insulation layer must be greater than 0.1mm.
On the other hand, in injection mo(u)lding, mold temperature (T
d) and cool time (θ) of needing between relation available following The Representation Equation usually:
θ＝-(D
2/2πα)·ln[(π/4){(Tx－Td)/(Tc－Td)}]
θ: cool time
D: the thickest of moulded products (cm)
T
c: barrel temperature (℃)
T
x: the fusing point of moulded products (℃)
α: the thermal diffusion coefficient of resin
T
d: mold temperature (℃)
Square being directly proportional of the thickest (D) of cool time and moulded products, and be (T
x-T
d) function.The effect that covers mould itself with thermal insulation layer is identical with the effect of the wall thickness that increases moulded products, makes cool time elongated.
As the synthetic resin of the thermal diffusion coefficient of the heat stable resin of thermal insulation layer and injection moulding much at one, therefore, make thickness increase 0.5mm, be equivalent to make the thickest increase 0.5mm of the moulded products in the above-mentioned equation as the heat-resistant resin layer of thermal insulation layer.Therefore, when making thickness as the heat-resistant resin layer of thermal insulation layer greater than 0.5mm, make molding cycle oversize, this is disadvantageous economically.
When the surface of mould itself is covered by the thermal insulation layer of being made up of heat stable resin and injects and the resin that heats when contacting with the surface of thermal insulation layer, the surface temperature of mould (thermal insulation layer) is owing to the heat of resin raises.The thermal conductivity of thermal insulation layer is more little and thermal insulation layer is thick more, and it is high more that the temperature of die face becomes.In the present invention owing to be injection mo(u)lding under low speed, preferably at the synthetic resin that injects with after the die face of cooling contacts, the time that mold face temperature remains the softening temperature that is not less than this resin was at least 0.4 second.For example, if die face does not have thermal insulation layer, the temperature of die face in 0.01 second, just become with the temperature of mould itself much at one.And in the present invention, be the thermal insulation layer covering mould of 0.1mm-0.5mm itself with thickness, die face was kept 0.4 second at the state that is not less than softening temperature.
During injection mo(u)lding, the variations in temperature of die face can be from synthetic resin, mould itself, calculating such as temperature, specific heat, thermal conductivity, density, crystallization latent heat as the heat-resistant resin layer of thermal insulation layer.For example, can be according to non-linear finite elements method, adopt ADINA, ADINAT etc. (software of Massachusetts Institute of Technology's exploitation), with instantaneous thermal conductance analytical calculation they.
Softening temperature described here is the temperature of synthetic resin can easily be out of shape the time, is Vicat softening temperature (ASTM D1525) for noncrystalline resin, is heat distortion temperature (ASTM D648, load 18.6kg/cm for the brilliant resin of scleroma
2), be heat distortion temperature (ASTM D648, load 4.6kg/cm for the brilliant resin of soft junction
2).The brilliant resin that hardens for example has polyoxymethylene, nylon 6 and nylon 6,6.The brilliant resin of soft junction for example has various polyethylene and polypropylene etc.
Low-pressure injection molding method of the present invention is the low a kind of injection moulding process of injection pressure that wherein synthetic resin and/or liquid is injected die cavity.Common injection moulding process is at about 1000kg/cm
2High injection pressure under carry out, low-pressure injection molding method of the present invention is not to be higher than a kind of low-pressure injection molding method that carries out under half the pressure of above-mentioned value comprising being injection-moulded in of low-pressure injection molding.
Low-pressure injection molding method of the present invention is at least a method that is selected from following injection moulding process: the injection moulding process that gas is auxiliary, the injection moulding process that liquid is auxiliary, the injection moulding process that oligomer is auxiliary, method for injection compression molding, core resin wherein are the sandwich injection moulding process and the Hettinga low-pressure injection molding methods of Foamex.
In low-pressure injection molding method of the present invention, carry out moulding by comprising the injection moulding that the flow velocity of synthetic resin in die cavity is not higher than the low speed injection moulding under the 100mm/s.Under this low speed injection moulding, can comprise various situations, as, the situation of the temporary transient step-down of injection moulding speed of synthetic resin, the situation that the mobile moment of synthetic resin stops, and the lower always situation of injection moulding speed.Injection moulding speed can from synthetic resin die cavity mobile distance and calculate as the injection screw of the measurement of the synthetic resin flowing time required time that advances.When with the auxiliary injection moulding molded synthetic resin of gas, during the injecting gas loading mould cavity, synthetic resin under high pressure injects generally speaking, then injecting gas under the pressure of half that is not higher than resin pressure then, after changing low-pressure gas into, the flow velocity of resin reduces greatly.High-pressure resin is replaced by the moment of low-pressure gas, has formed current mark usually, influences outward appearance.It is commonly called the slow-action impression.At the front area of slow-action impression, resin low speed flows, to the also common variation of the repeatability of die face.
To explain the present invention with reference to the accompanying drawings below.
At Figure 1A, among 1B and the 1C, synthetic resin 3 is injected in the die cavity 2 that mould itself 1 forms (Figure 1A), and injecting gas 5 then, to be full of die cavity 2 (Figure 1B), open mould 1 then, take out moulded products 6 (Fig. 1 C).Synthetic resin 3 injects under high injection pressure, and the pressure of injecting gas 5 is significantly less than the injection pressure of synthetic resin 3, and promptly the former is not higher than the latter half, and this is meaning this is a kind of low-pressure injection molding method.Therefore, when synthetic resin is replaced by gas in the injection moulding, the flow velocity of the synthetic resin of injection moulding in die cavity will change.Point 4 places in that flow velocity changes stay current mark on the surface of moulding article, it is generally known as the slow-action impression, influences outward appearance.In addition, the zone of slow-action impression and flow process end is to the repeatability variation of die face.In addition, owing to be potting resin under low flow velocity, the SCR variation of the moulded products that obtains.
The present invention is the molding methods that has solved the problems referred to above, promptly, the present invention is a kind of low-pressure injection molding method of synthetic resin, wherein, the mould that adopts with thickness greater than 0.1mm and be not more than the die cavity wall of one deck of 0.5mm as the heat stable resin covering metal die of thermal insulation layer itself, and at least partially under the low flow velocity that is not higher than 100mm/s in die cavity molded synthetic resin, carry out injection moulding.This method has reached following effect: moulded products does not have the resin reinforcing material to stretch out product surface basically, to the repeatability excellence of die face, and can make the injection moulded products of improved SCR.
Even the gas in the auxiliary injection moulding process of gas also can reach above-mentioned identical effect when changing one other fluid into.Fig. 2 is the temperature of various synthetic resin shown in the expression table 3 and fluid and the graph of a relation of viscosity.As long as their viscosity is not higher than 1/50 of synthetic resin viscosity, various fluids all can be by using as mentioned above.The auxiliary injection moulding process of liquid is to use liquid to replace the injection moulding process of gas as fluid, and the auxiliary injection moulding process of oligomer is to use low-molecular weight polymer to replace the injection moulding process of gas.Even in the auxiliary injection moulding process of the auxiliary injection moulding process of liquid and oligomer, also obtain with explaining Figure 1A 1B the same result during with 1C.
Table 3
| Symbol | Polymer |
| ?HIPS#492 | The polystyrene that rubber strengthens: Asahi chemical Polystyrene HIPS492 (Asahi chemical Indsutry co., Ltd. makes) |
| ?PP?M1500 | Polypropylene: Asahi chemical Polypro M1500 (Asahi chemical Indsutry co., Ltd. makes) |
| ?PE?J300 | High density polyethylene (HDPE): Suntec-HD J300 (Asahi chemical Indsutry co., Ltd. makes) |
| ?PS?SB150 | Low-molecular-weight polystyrene: (weight average molecular weight is 60 to Himer SB-150,000) (Sanyo chemical Industries, Ltd. makes) |
| ?PS?ST120 | Low-molecular-weight polystyrene: (weight average molecular weight is 10 to Himer ST-120,000) (Sanyo chemical Industries, Ltd. makes) |
| ?ED-PE800P | Low-molecular-weight and high density polyethylene (HDPE): (the viscosity method: mean molecule quantity is 8 to Hi-Wax 800P, 000) (Mitsui petrochemical Indsutries, Ltd. makes) |
| ?LD-PE720P | Low-molecular-weight and low density polyethylene (LDPE): (the viscosity method: mean molecule quantity is 7 to Hi-Wax 720P, 200) (Mitsui Petrochemical Indsutries, Ltd. makes) |
| ?LD-PENL800 | Low-molecular-weight and low density polyethylene (LDPE): (the viscosity method: mean molecule quantity is 6 to Hi-Wax NL800,400) (Mitsui Petrochemical Industries, Ltd. makes) |
| ?PP?550P | Low-molecular-weight is gathered two alkene: Viscol 550-P (vapour pressure osmotic pressure method: mean molecule quantity is 4000) (Sanyo chemical Indsutries, Ltd. makes) |
| ?PEG?6000 | Polyethylene Glycol: (weight average molecular weight is 7 to Macrogol 6000,500) (Wako Pure chemical Industries, Ltd. makes) |
Fig. 3 A and 3B represent another moulded products with the auxiliary injection moulding process moulding of gas.In Fig. 3 A and 3B, in moulded products 7, the terminal thick wall area 10 that forms of 9 flow process from cast gate 8 to resin.When from cast gate 8 injection synthetic resin, then during injected gas, gas-selectively ground advances by thick wall area, and formation is generally known as the hollow region of gas passage 11.By means of the pressure of the gas in the gas passage 11, the pressure of injected gas is transferred to the flow process end of resin 9 equably.A-A ' cross-sectional view of the moulded products among Fig. 3 A is shown among Fig. 3 B.Even in above-mentioned moulding article, also can produce as explaining Figure 1A, described repeatability and problem such as SCR to die face when 1B and 1C, and in the present invention, use is coated with the metal die of the heat-resistant resin layer of suitable selection, can obtain gratifying moulded products.
Fig. 4 A and 4B represent method for injection compression molding, and it is a kind of in the low-pressure injection molding method described in the present invention.In Fig. 4 A and 4B, retreat slightly by the matched moulds plate that makes injection machine, a removable rear flank of mould 1 is moved back and die cavity 2 thickenings (heavy wall), injecting synthetic resin 3 (Fig. 4 A), the matched moulds plate is advanced, thereby the removable side of mould 1 is advanced, make die cavity return to preset thickness (wall thickness), synthetic resin is under low pressure charged into die cavity (Fig. 4 B) like this.In conventional method, behind injecting synthetic resin, the thickness of die cavity (wall thickness) is when beginning to reduce usually, and the flow velocity of synthetic resin in die cavity changes usually, and produces current mark at point 4 places that change, and has influenced outward appearance.In addition, by the thickness (wall thickness) that reduces die cavity, under low pressure during loading mould cavity, the flow velocity step-down of synthetic resin in die cavity, therefore, to the repeatability variation of die face, its gloss is variation also in that zone for moulded products.In addition, because the flow velocity step-down of synthetic resin in die cavity, the SCR of moulding article is variation also.And in the present invention,, improved above-mentioned relatively poor outward appearance and SCR by using the mould of the heat stable resin covering of suitably selecting by one deck.
Below with reference to Fig. 5 to Figure 12, to the repeatability of die face and the reason of SCR extreme difference, and cover mould according to the present invention with the specific heat stable resin of one deck and can improve their reason in the low pressure injection formaing method of interpretation routine.
Fig. 5,6,7 and 8 to be illustrated in the mould self-temperature be polystyrene that 50 ℃, rubber strengthen when being 240 ℃ of following injection mo(u)ldings, near the synthetic resin layer the mould wall is or/and the temperature distribution history of heat-resistant resin layer (calculated value).Among the figure, the resin of the numeric representation heating on each curve contacts back elapsed time (second) with the die wall of cooling.Be cooled after the synthetic resin of heating contacts with die wall, face raises by the heat temperature that absorbs the synthetic resin that heats simultaneously at once.As shown in the figure, when the heat stable resin (polyimides) of using one deck as thermal insulation layer covers die face (Fig. 6 and 7), the temperature on the surface of the heat-resistant resin layer that contacts with synthetic resin raises and becomes big, and underspeeding of temperature diminishes.
When covering die face with one deck heat stable resin, elapsed time was short more after synthetic resin contacted with die wall, and the temperature of die face is high more, thereby was equivalent to improve greatly mold temperature with one deck heat stable resin covering mould.
Fig. 8 represents to contact with this surface with resin as the polyimide surface temperature of thermal insulation layer the variation of back elapsed time.In order to make mold face temperature after resin contacts 0.4 second with die face, still remain the softening temperature that is not less than synthetic resin, need to cover greater than the polyimides of 0.1mm the surface of metal die with thickness.The thickness of heat-resistant resin layer changes according to the softening temperature of mold temperature and synthetic resin, but generally speaking, carry out injection moulding in mold temperature under near 50 ℃, the softening temperature of the actual synthetic resin that uses is not more than about 100 ℃, determines thickness as the heat stable resin of thermal insulation layer based on this.
As in the present invention, therein in the conventional low-pressure injection molding method that the flow velocity of synthetic resin in die cavity is low, touching to be applied on the die wall surface that is touched from synthetic resin and die wall is enough to make synthetic resin to reproduce between the injection pressure of die face to need a period of time.Mold face temperature has reduced when therefore, applying injection pressure.When the injection moulding process that changes suddenly with resin flow velocity wherein carried out moulding, its outward appearance was easy to unexpected variation at resin change in flow place.In the present invention, by means of the thermal insulation layer of thickness, restrained the variation of resin outward appearance greater than 0.1mm.In addition, under synthetic resin still can keep being not less than the condition of softening temperature of synthetic resin at least in after die face contacts 0.4 second, carry out injection moulding, improved outward appearance at mold face temperature.
Fig. 9 represents the flow graph of synthetic resin in die cavity, and Figure 10 represents because the heat that the mobile shearing of synthetic resin produces.
In Fig. 9, when the synthetic resin of heating and plasticizing was injected in the die cavity of mould 12 of cooling, the synthetic resin of injection contacted with the die wall of cooling and also forms cured layer 13 immediately.The synthetic resin that injects advances on cured layer continuously, arrives after the front 14 of flowing, and becomes the so-called current of spring (fountain flow) 15 that points to die wall.Shown in velocity flow profile curve 18, the fastest at the flow velocity 16 of die cavity center 17 synthetic resin, more near cured layer 13, flow velocity is slow more.In the synthetic resin of flowable state, shown in the distribution curve 19 of shear rate, produced shearing force, produced the heat that is directly proportional with shearing force.The heat that produces during the injection moulding speed dog is very big, and is producing heat near the cured layer place, and this can stop the further increase of cured layer.Figure 10 has represented to produce the degree of heat.The Temperature Distribution of synthetic resin when filling mould under the different synthetic resin flow velocity that Figure 10 represents to obtain based on the heat that following condition calculating produces:
Mould: ferrous materials
Cavity dimension: 60 * 290 * 2mm (wide * long * thick)
Synthetic resin: Asahi Chemical polystyrene 492
The temperature of synthetic resin: 240 ℃
Mold temperature: 50 ℃
The time of injection moulding mold filling: 0.1 second, 0.4 second and 1.0 seconds
Calculate the software that uses:
The MOLD FLOW/FLOW that MOLD FLOW PTY Ltd. produces
Provided behind the potting resin, apart from the cross section Temperature Distribution of the resin at cast gate 25mm (A), 145mm (B) and 265mm (C) three places.Generally, when the flow velocity of synthetic resin was big, the heat of generation was very big, and produced heat along cured layer, has therefore suppressed the growth of cured layer and resin is filled under the thin state of cured layer.In other words, in the traditional injection moulding method, owing to self give birth to the further growth that heat has suppressed cured layer, carry out moulding under the situation of flow channel having.And in the low speed injection moulding identical with the present invention, because flow velocity is little, little, the cured layer thickening of heat that produces when flowing, thereby resin is filled under the thicker state of cured layer.In the low speed injection moulding, from aforesaid flow regime as can be seen, injection mo(u)lding is carried out under very disadvantageous condition.Like this, it is relatively poor that the cured layer thickening makes the SCR of moulded products.
Below with reference to Figure 11 A and 11B, illustrate that the present invention can improve SCR.The low speed injection moulding makes the cured layer thickening, the SCR variation.In the present invention, for improving this situation, use to be coated with the mould that one deck heat stable resin is made thermal insulation layer.
In Figure 11 A and 11B, with the cooling the metal die molded synthetic resin time, the molten resin of injection moulding contacts with the die wall of cooling, forms cured layer 20 on the die wall surface immediately, cured layer 20 plays the effect of thermal insulation layer like this, and core 21 cools off gradually and shrinks.In the moulded products of fully cooling, because the contraction of core 21 makes and residual in the superficial layer 20 compression stress is arranged, and the ratio of the thickness S of the thickness C of compressive residual stress and core 21 and superficial layer 20 is C/S be directly proportional (I of Figure 11 A).Compare with using the conventional mould do not cover thermal insulation layer, the present invention uses and is coated with one deck heat stable resin when making the mould of thermal insulation layer and carrying out injection moulding, and the superficial layer 20 that at once forms after the injection moulding is thinner.The compressive residual stress of abundant cooled moulded products increases (I of Figure 11 B) with C '/S ' value, therefore compare with the situation of using the mould that does not cover the heat stable resin thermal insulation layer to carry out injection moulding, the compressive residual stress of the moulded products that the inventive method makes is big.When the goods after injection mo(u)lding applied bending stress, the compression stress of moulded products concave side 22 became bigger, and the compression stress of convex side 23 disappears, and was applied in tensile stress (II of Figure 11 A, the II of Figure 11 B).In Figure 11 B, when the compressive residual stress of superficial layer was big, the tensile stress of superficial layer was little when crooked.Generally speaking, because big many of the compressive strength specific tensile strength of synthetic resin, when the moulded products of synthetic resin applied bending stress, the convex side of goods at first broke.Therefore, in Figure 11 B, the tensile stress of moulded products superficial layer diminishes, thereby almost can not be destroyed.Like this, use the moulded products of the mold injection that is coated with the heat stable resin thermal insulation layer more to be not easy to destroy.This may be a big reason of SCR change of injection moulded products of the present invention.
Below with reference to Figure 12, the low reason of the flow velocity of synthetic resin in die cavity in low pressure injection formaing is described.Figure 12 is illustrated in the resin pressure that is applied in the injection mo(u)lding on the die wall over time, and shows the difference of the auxiliary injection moulding process of conventional injection moulding process and gas.Figure 12 shows near pressure curve A and a the cast gate, the pressure curve B and the b at place in the middle of near pressure curve C the flow process end and c and the flow process.In the traditional injection moulding method, applied pressure is with curve A and A ' rising near the cast gate, when full notes (full shot), reach peak, locating applied pressure on stream raises along curve B, when completely annotating, reach peak, applied pressure raises along curve C near the flow process end, reach peak when completely annotating, and they reduces with the expansion time all.With close cast gate, the peak of curve A, B and C is big more, and final applied pressure changes with the position.
On the other hand, in the auxiliary injection moulding process of gas, at first under high pressure inject resin, stop to inject resin in the middle of injection moulding, injection pressure is significantly less than the gas of the injection pressure of resin then, is full of die cavity.In the auxiliary injection moulding process of this gas, near the pressure the cast gate at first raises along curve A, and resin is replaced by the point 24 of gas in the middle of injection moulding, and it is almost identical with gas pressure that resin pressure becomes, and after this keeps constant voltage to move along curve a.Behind the injecting gas, the resin pressure of locating in the middle of the flow process is along curve b rising and become almost identical with gas pressure when completely annotating, and keeps this pressure in expansion process.Flow near the front resin pressure shown in curve c, and when completely annotating, become almost identical, and in expansion process, keep this pressure with gas pressure.The auxiliary injection moulding process of gas is characterised in that the pressure of the pressure at place and flow process end is nearly all identical in the middle of near the pressure when completely annotating the cast gate, the flow process.Therefore, in the auxiliary injection mo(u)lding of gas, the residual stress accuracy to size very even, goods that becomes is fabulous in the moulded products, thereby is widely used.But shown in curve b and c, in the auxiliary injection mo(u)lding of gas, the mode that resin pressure raises is slower, so this part flow velocity in die cavity is slack-off, thereby makes the outward appearance and the SCR variation of the moulded products of this part.As mentioned above, the present invention reaches the purpose of improving above-mentioned defective by cover the surface of mould itself with heat stable resin.
Use low-pressure injection molding method of the present invention, can obtain having improved gloss, indenture and slow-action impression, and the injection moulded products of outward appearance and SCR excellence.
According to the following example, will illustrate in greater detail the present invention, but the present invention is not subjected to the restriction of these embodiment.
In an embodiment, following mould, material and measuring method have been used.
(1) mould itself 1: (S55C) makes by steel, and cavity dimension is 2mm (thick) * 100m * 100m, has side gate, and die face chromium plating is as minute surface.
(2) mould itself 2: (S55C) makes by steel, and its die cavity is a rectangle, and size 3mm (thick) * 70mm * 378mm has the rib line that is of a size of 5mm * 5mm at length direction, and side gate is positioned on the angle.Die face chromium plating is as minute surface.
(3) polyimides after the precursor of polyimides and the curing: the solution of the precursor of high-molecular linear polyimides " Torayneece # 300 " (Toray Industries, Inc. makes).The performance of the polyimides after the curing is: Tg300 ℃, thermal conductivity 0.0005cal/cmsec ℃, tensile fracture elongation is 60%.
(4) metal die that covers with polyimides: the solution coat mould of using the precursor of polyimides itself, be heated to 160 ℃, make its part imidizate, repeat coating then and be heated to 160 ℃ 2 to 8 times, be heated to 290 ℃ at last, make imidizate reach 100%.Like this, die face is covered by polyimides.With the die face polishing, make it as minute surface, preparation is coated with the mould that thickness is the polyimides of 0.025mm, 0.05mm, 0.075mm, 0.1mm, 0.15mm, 0.16mm and 0.175mm respectively.
(5) epoxy resin of modification: " Cemedine EP-007 " (CemedineCorporation manufacturing), the performance after the curing is thermal conductivity 0.0005cal/cmsec ℃, tensile fracture elongation 12%, pencil hardness H.
(6) metal die that covers with modified epoxy: the epoxy resin coating die itself 1 with modification, be heated to 50 ℃, subsequently to 100 ℃, solidify then.Make it as minute surface the die face polishing.
(7) treat the synthetic resin of injection mo(u)lding:
HIPS492: the polystyrene " Asahi ChemicalPolystyrene492 " that rubber strengthens, Asahi Chemical Industry Co.Ltd. makes.
HIPS495: the polystyrene " Asahi ChemicalPolystyrene495 " that rubber strengthens, Asahi Chemical Industry Co.Ltd. makes.
PMMA: methacrylate resin " Delpet 80N ", AsahiChemical Industry Co.Let. makes.
(8) method of measurement gloss: according to JIS K7105 (reverberation angle: 60 ℃)
(9) method of measurement SCR: according to cantilever method shown in Figure 13.In Figure 13, make the sample 25 that bears bending stress (after being of a size of 2 * 20 * 100mm) point 26 solvent contacts, add load 27, observe owing to cracking the required time that fractures.
Embodiment 1
Use mould itself 1 and carry out the injection mo(u)lding test of PMMA with thickness as the mould 1 of the polyimides covering of 0.175mm itself.The condition of injection mo(u)lding is: 260 ℃ of injecting machine material tube temperatures, 60 ℃ of mold temperatures, change injection pressure, the low speed injection moulding and the described flow velocity that carry out the mean flow rate of synthetic resin in die cavity and be 13mm/ second are the 230mm/ high speed injection motding of second, measure the SCR of injection moulded products according to rupture time, the results are shown in table 4.
The moulded products that use is coated with the metal die of polyimides has improved SCR.Particularly in the low speed injection moulding, improved effect is more obvious.
Table 4
| Surface stress (kg/cm 2) | Rupture time | |||
| The low speed injection moulding | High speed injection motding | |||
| The chrome-plated metal mould | Cover the metal die of polyimides | The chrome-plated metal mould | Cover the metal die of polyimides | |
| ????130 | 1.4 | 16 minutes | 2.2 minute | 11 minutes |
The low speed injection moulding: the flow velocity of synthetic resin in die cavity is 13mm/s.
High speed injection motding: the flow velocity of synthetic resin in die cavity is 230mm/s.
Cover the metal die of polyimides: the thickness of polyimide layer is 0.175mm.
Use mould itself 1 and, carry out the injection mo(u)lding of HIPS495 with the mould 1 of the polyimides covering of different-thickness itself.The injection mo(u)lding condition is: 220 ℃ of barrel temperatures, 35 ℃ of mold temperatures.By changing injection pressure, correspondingly change injection moulding speed, and further change the thickness of polyimide layer, measure the gloss of moulded products, and be shown in (thickness of the value representation polyimides thermal insulation layer among Figure 14 A on the curve, the flow velocity of the numeric representation synthetic resin among Figure 14 B on the curve) among Figure 14 A and the 14B.
The flow velocity difference of synthetic resin in die cavity, the gloss difference of moulded products is very big, does not show in order not to be higher than at flow velocity in the 100mm/ low speed injection moulding of second to obtain high gloss, and the thickness that requires polyimides preferably is not less than 0.15mm greater than 0.1mm.
The mould itself 2 that uses two kinds of mould-moulds 2 itself and cover with the thick polyimides that becomes 0.16mm, adopt four kinds of injection molding forming method-conventional high speed injection moldings, conventional low speed injection mo(u)lding, auxiliary injection mo(u)lding and the auxiliary injection mo(u)lding of oligomer of gas, carry out injection mo(u)lding.HIPS492 is as synthetic resin, uses as the table 3 of oligomer and the polystyrene STl20 shown in Figure 2 and the blend of azo dicarbonamide CBA.During injection mo(u)lding, barrel temperature is 230 ℃, and mold temperature is 40 ℃.
Every kind of injection moulding process of permutation and combination and every kind of mould carry out injection mo(u)lding, measure every kind of moulded products gloss, whether indenture is arranged, whether the slow-action impression is arranged at the dorsal part of rib line, the results are shown among table 5 (a) and 5 (b).
In table 5 (a) and 5 (b), in the injection moulding that comprises low speed injection moulding B, C and D, when the mould of use chromium plating carried out injection mo(u)lding, the gloss of flow process end was very poor.And use the metal die that covers with polyimides, even when the low speed injection moulding, the gloss of flow process end is also good.
Figure 15 A and 15B show the injection molding forming method auxiliary according to oligomer respectively, use respectively with the mould of polyimides covering and the mould (mould itself) of chromium plating, near the cross cutting face schematic diagram of the flow process end of the moulded products that makes superficial layer.These figure draw according to transmission electron microscope picture (TEM) (amplifying 5000 times).When use was coated with the mold injection molding of polyimides, the surface of moulded products 29 does not have rubber grain 28 to extend out basically, and was fabulous to the repeatability of die face.
The low-pressure injection molding method according to the present invention, when the mould that use is coated with polyimides carries out injection mo(u)lding, the injection mo(u)lding auxiliary as gas, the injection mo(u)lding that liquid is auxiliary, the injection mo(u)lding that oligomer is auxiliary etc., the low-pressure injection molding methods such as accuracy to size height that keep the low and moulded products of mold clamping force warpage low, moulded products by intrinsic advantage outside, also make moulded products improve gloss, indenture and slow-action impression.
Be similar to embodiment 2, use mould itself 1 and carry out injection mo(u)lding with the mould 1 of the modified epoxy covering of different-thickness itself.Obtain result similar to Example 2.
Table 5 (a)
| ????????????A | ????????????B | ????????????C | ?????????????D | |||||
| Conventional high speed injection motding method | Conventional low speed injection moulding process | The injection moulding process that gas is auxiliary | The injection moulding process that oligomer is auxiliary | |||||
| Chrome-plated mould | Metal die with the pI covering | Chrome-plated mould | Metal die with the PI covering | Chrome-plated mould | Metal die with the PI covering | Chrome-plated mould | Metal die with the PI covering | |
| Injection pressure (Kg/cm 2) | ????1100 | ????1100 | ????800 | ????800 | ?1100→100 | ?1100→100 | ?1100→500 | ?1100→500 |
| Flow velocity in die cavity (mm/sec.) | ????220 | ????220 | ????50 | ????50 | ?220→20 | ?220→20 | ?220→80 | ?220→80 |
Annotate: PI represents polyimides
Table 5 (b)
| ????????????A | ??????????????B | ???????????C | ????????????D | ||||||
| Conventional high speed injection motding method | Conventional low speed injection moulding process | The injection moulding process that gas is auxiliary | The injection moulding process that oligomer is auxiliary | ||||||
| Chrome-plated mould | Metal die with the PI covering | Chrome-plated mould | Metal die with the PI covering | Chrome-plated mould | Metal die with the PI covering | Chrome-plated mould | Metal die with the PI covering | ||
| Gloss (%) | Near the cast gate | ????53 | ????100 | ????32 | ????90 | ????54 | ????97 | ????51 | ????99 |
| In the middle of the flow process | ????53 | ????98 | ????19 | ????88 | ????41 | ????95 | ????50 | ????98 | |
| The flow process end | ????45 | ????95 | ????13 | ????85 | ????17 | ????94 | ????35 | ????95 | |
| The indenture of rib line dorsal part | Have | Have | Have | Have | Do not have | Do not have | Do not have | Do not have | |
| The slow-action impression | Do not have | Do not have | Do not have | Do not have | Have | Do not have | Have | Do not have | |
Annotate: PI represents polyimides
Use low-pressure injection molding method of the present invention, can obtain having improved gloss, indenture and slow-action impression, and have the injection moulded products of excellent appearance and stress crack resistance performance (SCR).
Claims (9)
1. the low-pressure injection molding method of synthetic resin, wherein, the mould that uses, and will synthesize injection moulding under the 100mm/ low flow velocity of second and go in the die cavity at least partially in not being higher than greater than 0.1mm and be not more than the die cavity wall of the heat stable resin covering metal die of 0.5mm itself with a layer thickness, carry out injection moulding.
2. according to the low-pressure injection molding method of claim 1, wherein, containing resin in the described synthetic resin increases material, and the moulded products behind the resin forming does not have the resin reinforcing material to stretch out the surface of goods basically.
3. according to the low-pressure injection molding method of claim 2, wherein, the described synthetic resin that contains the resin reinforcing material is the synthetic resin that rubber strengthens.
4. according to the low-pressure injection molding method of claim 3, wherein, the synthetic resin that described rubber strengthens is the phenylethylene resin series that rubber strengthens.
5. according to the low-pressure injection molding method of claim 1, wherein, the thickness of heat-resistant resin layer is in 0.15mm-0.45mm scope.
6. according to the low-pressure injection molding method of claim 2, wherein, the thickness of heat-resistant resin layer is in 0.15mm-0.45mm scope.
7. according to the low-pressure injection molding method of claim 3, wherein, the thickness of heat-resistant resin layer is in 0.15mm-0.45mm scope.
8. according to the low-pressure injection molding method of claim 4, wherein, the thickness of heat-resistant resin layer is in 0.15mm-0.45mm scope.
9. according to the low-pressure injection molding method of arbitrary requirement in the claim 1-8 wherein, described low-pressure injection molding method is at least a method that is selected from following injection moulding process: the injection moulding process that gas is auxiliary, the injection moulding process that liquid is auxiliary, the injection moulding process that oligomer is auxiliary, injection compression molding method, core resin are the sandwich injection moulding process and the Hettinga low-pressure injection molding method of Foamex.
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| PCT/JP1994/001499 WO1996007527A1 (en) | 1994-09-09 | 1994-09-09 | Low-pressure injection molding method |
| CN94190340.0A CN1127491A (en) | 1994-09-09 | 1994-09-09 | Low-pressure injection molding method |
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| PCT/JP1994/001499 WO1996007527A1 (en) | 1994-09-09 | 1994-09-09 | Low-pressure injection molding method |
| CN94190340.0A CN1127491A (en) | 1994-09-09 | 1994-09-09 | Low-pressure injection molding method |
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| WO (1) | WO1996007527A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102947071A (en) * | 2010-06-23 | 2013-02-27 | 宝洁公司 | High velocity injection molded product |
| CN104249433A (en) * | 2013-06-26 | 2014-12-31 | 合肥杰事杰新材料股份有限公司 | Processing method for low pressure injection molding of refrigerator inner container by using high impact polystyrene |
| CN104669643A (en) * | 2013-11-26 | 2015-06-03 | 比亚迪股份有限公司 | Apparatus and method for producing fiber composite shell |
| CN106426743A (en) * | 2016-10-07 | 2017-02-22 | 吉林省华翼汽车零部件有限公司 | Low-pressure injection molding backrest protecting plate |
| CN110734291A (en) * | 2019-10-31 | 2020-01-31 | 陕西博鼎快速精铸科技有限责任公司 | Processing method for ceramic mold injection molding of high-temperature-resistant polymer parts |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104249448B (en) * | 2013-06-27 | 2018-03-02 | 合肥杰事杰新材料股份有限公司 | A kind of processing method of ABS resin low-pressure injection molding inner container of icebox |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2714308B2 (en) * | 1992-03-06 | 1998-02-16 | 旭化成工業株式会社 | New injection molding method |
| JPH06246797A (en) * | 1992-12-28 | 1994-09-06 | Nippon Steel Chem Co Ltd | Prevention of generation of sink in appearance surface of molded product and injection mold |
-
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102947071A (en) * | 2010-06-23 | 2013-02-27 | 宝洁公司 | High velocity injection molded product |
| CN104249433A (en) * | 2013-06-26 | 2014-12-31 | 合肥杰事杰新材料股份有限公司 | Processing method for low pressure injection molding of refrigerator inner container by using high impact polystyrene |
| CN104669643A (en) * | 2013-11-26 | 2015-06-03 | 比亚迪股份有限公司 | Apparatus and method for producing fiber composite shell |
| CN106426743A (en) * | 2016-10-07 | 2017-02-22 | 吉林省华翼汽车零部件有限公司 | Low-pressure injection molding backrest protecting plate |
| CN110734291A (en) * | 2019-10-31 | 2020-01-31 | 陕西博鼎快速精铸科技有限责任公司 | Processing method for ceramic mold injection molding of high-temperature-resistant polymer parts |
| CN112277235A (en) * | 2020-09-18 | 2021-01-29 | 中国航发北京航空材料研究院 | Injection molding method of oversized polymer glass |
| CN112277235B (en) * | 2020-09-18 | 2022-05-17 | 中国航发北京航空材料研究院 | Injection molding method of oversized polymer glass |
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