JP2001232661A - Molding method for obtaining molded article reduced in optical strain, and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding a transparent thermoplastic resin to obtain a product having good optical characteristics, more precisely, a large- sized glazing product such as a car glazing product good in optical strain characteristics, and the obtained molded product. SOLUTION: A molded article having a multilayered structure reduced in optical strain is obtained by (1) a process for preliminarily mounting a transparent resin sheet on the surface of a mold cavity as a first layer and subsequently mounting the transparent resin sheet on the surface of a mold core as a second layer, (2) a process for filling the space between the first and second layers with a transparent thermoplastic resin (hereinbelow referred to as 'resin b1') as a third layer at an injection speed of 300 mm/sec or more and (3) a process for allowing compression force to act on the molded article having the multilayered structure consisting the first, second and third layers while cooling the molded article until capable of taking the same out of a mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for molding a transparent thermoplastic resin to obtain a product having good optical properties, and to such a molded product. More specifically, a method for molding a transparent thermoplastic resin for obtaining a large glazing product, such as a helmet windshield, a glazing product for a construction machine, an automobile, a bus, etc., which has conventionally been manufactured mainly by hot bending of a sheet molded product. And such large glazing products.

[0002]

2. Description of the Related Art Helmet windshields, construction machinery, automobiles,
Large glazing products made of resin, such as glazing products such as baths, have conventionally been manufactured mainly by the method of hot bending sheet molded products.In recent years, injection molding has been used for the purpose of manufacturing efficiency and freedom of design. Attempts have been made to manufacture. In such a case, it is needless to say that it is required to produce a molded product having little optical distortion.

[0003] As a molding method of a transparent thermoplastic resin optical product, there have been conventionally a method of injection molding with a mold temperature being higher than the glass transition temperature of the resin, and a method in which the cavity volume is larger than the product volume and the pressure is low. Many molding methods such as an injection compression molding method of filling a resin and then compressing the resin have been proposed. However, it has been pointed out that none of the injection molding methods is still sufficient to obtain a product having good optical distortion characteristics.

As a method for solving such a problem, Japanese Patent Application Laid-Open No. 61-79614 discloses an optical disk having a low distortion by performing filling while a mold surface is locally heated to a high temperature in molding an optical disk, and thereafter compressing. Is proposed to be obtained. However, in such a method, when a large-sized molded product is molded, a large unevenness occurs in the history of distortion and heat applied to the resin at the time of filling in the mold. The resulting distortion is not eliminated, and a product with sufficient optical distortion cannot be obtained.

Similarly, in Japanese Patent Application Laid-Open No. 7-256704, a molded article having a small image distortion can be obtained by using a mold having a heat-insulating layer to similarly raise only the surface of the mold cavity and using injection compression molding. However, it was not sufficient for large molded products.

That is, although it is desired to produce a large-sized resin molded product with little optical distortion by an injection molding method, there has been no such production method.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for molding a transparent thermoplastic resin for obtaining a product having good optical properties, and to provide such a product. More specifically, it is an object of the present invention to provide a method for molding a transparent thermoplastic resin for obtaining a large glazing product such as an automobile glazing product having good optical distortion characteristics, and to provide such a product.

As a result of intensive studies to solve the above problems, the present inventors have found that when performing injection compression molding, a transparent thermoplastic resin sheet is mounted on the surface of a mold cavity and the surface of a core, and a specific The present inventors have found that by filling a resin at a high speed higher than the injection speed, a desired good product can be obtained, and arrived at the present invention.

[0009]

SUMMARY OF THE INVENTION The present invention provides a method for obtaining a molded article having a multilayer structure having a small optical distortion. (1) The first layer is formed on the surface of the mold cavity in advance and the second layer is formed on the mold. A transparent thermoplastic resin sheet is mounted on each of the core surfaces, and (2) a transparent thermoplastic resin (hereinafter sometimes referred to as “resin b”) as a third layer in a space between the first layer and the second layer. ) Is filled at an injection speed of 300 mm / sec or more, and (3) While cooling such a multilayer structure molded product comprising the first layer, the second layer, and the third layer until it can be taken out of the mold, The present invention relates to a molding method for obtaining a multilayer molded article having a small optical distortion by applying a compressive force, and a product thereof.

According to the present invention, (1) a transparent thermoplastic resin sheet is previously mounted on a surface of a mold cavity as a first layer and on a surface of a mold core as a second layer, respectively.
One requirement is to fill the space between the layer and the second layer with a resin that forms the third layer (hereinafter, may be referred to as “requirement (1)”). By filling the resin between the two layers, unlike the case where the resin is directly in contact with the surface of the mold cavity or the surface of the mold core, the portion to be rapidly cooled in the cooling process is reduced, and the resin is gradually cooled by the heat insulating effect of the sheet. Become like That is, the difference in the thermal history in the thickness direction is reduced, so that a uniform layer can be formed in the thickness direction.

In the present invention, the mold cavity surface refers to the surface of the mold cavity in the fixed mold.
The mold core surface refers to the surface of the mold cavity in the movable mold. The mold cavity refers to a portion of the mold that is filled with resin to obtain a molded article main body (excluding runners and sprues).

The transparent thermoplastic resin forming the first, second and third layers of the present invention is JIS standard K71.
Haze of a 2 mm-thick flat plate molded product conforming to H.05 refers to 10% or less, preferably 9% or less. Specific resins include polycarbonate resin, acrylic resin, rubber-reinforced acrylic resin,
Amorphous polyolefin resin, amorphous polyarylate resin, amorphous polyester resin, polystyrene resin, acrylonitrile styrene (AS) resin, methacrylate acrylonitrile styrene (MAS) resin, transparent A
A transparent resin such as a BS resin can be used. Among them, polycarbonate resin, acrylic resin, rubber-reinforced acrylic resin, amorphous polyolefin resin, amorphous polyarylate resin, and amorphous polyester resin are preferable.
The resin forming the layer is most preferably a polycarbonate resin in terms of strength, impact resistance, heat resistance and the like, and the resin forming the first layer and the second layer is also preferably a polycarbonate resin for the same reason.

The transparent thermoplastic resin sheet used in the present invention can be prepared by a general melt extrusion method, an inflation method or the like.
Methods such as a casting method and a powder molding method can also be used. Further, in such a method, it is possible to obtain a sheet having a small heat history by directly forming the sheet from a molten state such as a melt transesterification reaction or the like in a production step of the raw resin or a solution state after polymerization. It is.

In the present invention, JIS standard R3 is more preferable.
When the angle between the normal to the projection plane and the normal to the sheet plane measured at 55 ° is 55 °, the amount of perspective distortion is 1.5.
Minutes or less are used. In order to create such a sheet, in each of the above-described methods, an operation such as excessive compression or stretching is not performed, or a sheet having a large amount of perspective distortion due to the processing is sufficiently annealed. It is preferable to remove such distortion. From such a point, the sheet is preferably formed by a melt extrusion method using a T-die or an I-die, and particularly a so-called calender roll type. Such a method achieves both uniformity of thickness and low distortion.

The thickness of such a sheet is usually 50 to 50.
It is 2000 μm, preferably 100-1000 μm, more preferably 200-700 μm. When the thickness is smaller than 50 μm, the heat insulating effect of the sheet is not sufficient. In addition, when mounted on the cavity surface and the core surface of the mold, the rigidity is weak, and depending on the mold structure, it may deviate from the cavity surface and the core surface of the mold, and further depending on the resin temperature of the molten resin b. Is partially melted and cannot keep its shape.

In the case of a thermoplastic resin sheet having a thickness of more than 2000 μm, it is difficult to reduce the distortion of the sheet itself, and productivity is inferior due to the number of steps required for the reduction.

Further, the thickness ratio of the first layer and the second layer is determined from the viewpoint of securing the same thermal history on both layer sides.
The second layer is preferably 1: 9 to 9: 1, more preferably 3: 7 to 7: 3.

On the other hand, in order to obtain a molded product having a low distortion which is the object of the present invention, the thickness of the first layer and the second layer is determined by designing the thermoplastic resin, the main mold and the first layer and the first layer during molding. By calculating from the temperature, specific heat, thermal conductivity, density, latent heat of crystallization, and the like of the second layer, it is possible to analyze the thermal history of the third layer and calculate the optimum thickness from this.
In particular, a design capable of maintaining a temperature higher than the glass transition temperature of the thermoplastic resin of the third layer for at least 0.1 second is preferable, using the temperature of the surface of the third layer that is in contact with the thermoplastic resin sheet as an index, It is more preferable to design the sheet thickness, molding conditions, and apparatus environment that can be maintained more preferably for 1 second or longer, and as an upper limit within 60 seconds.
Such calculations are, for example, ADINA and ADINA-
Using T (name of software developed at the Massachusetts Institute of Technology) and the like, it can be calculated by an unsteady heat conduction analysis by a nonlinear finite element method.

When the stretching ratio of the thermoplastic resin sheet locally increases depending on the shape of the product, the thermoplastic resin sheet may be formed by a straight molding method, a drape molding method, a plug assist molding method, an air blow molding method, or the like. It is also possible to use a material which has been given a shape in advance by a conventionally known method such as a method of heating vacuum forming, a method of hot press forming, and a method of heating and pressure forming. Further, the preforming step of giving a shape to the thermoplastic resin sheet in advance may be performed in an injection molding die from the viewpoint of improving the efficiency of the step.

Further, as the thermoplastic resin sheet used in the present invention, a sheet which has been subjected to a treatment such as hard coating or printing in advance can be used.

In the present invention, a known hard coat agent can be used as a compound for forming a crosslinked film as a hard coat film on a thermoplastic resin sheet. As a hard coating agent, a resin having a high surface hardness, for example, an acrylic resin,
Melamine-based, urethane-based, epoxy-based, and other known silicone-based hard coat agents such as those capable of having a hard coat property equivalent to that of glass by a siloxane bond in an organosiloxane resin can be used.

As the curing method, known methods such as ultraviolet curing, heat curing, electron beam curing, infrared irradiation, and hot air drying may be used alone or in combination. In such a case, especially when the stretching ratio of the thermoplastic resin sheet locally increases as shown above, after hardening the hard coat agent to such an extent that it is not completely hardened, without shaping,
Or after shaping and molding to form a multilayer structure molded product,
A method of completely hardening the hard coat agent can be used. Also, the hard coat agent itself is applied as a gel or sol having a partially cross-linked structure, and then molded without shaping or by shaping to form a multilayer structure molded article, and then the hard coat agent Can be completely cured.

When the resin material is a polycarbonate or a heat-resistant acrylic resin, it is particularly preferable to provide a primer layer having good adhesion between the hard coat agent and the resin, and it is not particularly limited. An acrylic resin containing an ultraviolet absorber can be used.

Known methods such as a bar coating method, a spray coating method and a roll coating method can be used as a method for applying the hard coat film forming raw material. The thickness of the lamination sheet thus obtained is determined by the appearance of a molded product, impact resistance, abrasion resistance, weather resistance and the like. The thickness is preferably 1 to 50 μm, more preferably 3 to 30 μm
It is. If the thickness of the hard coat film is less than 1 μm, sufficient abrasion resistance cannot be obtained, and if the thickness is more than 50 μm, the flexibility of the coating film decreases and cracks occur due to bending and the like. At the time of coating, an organic solvent may be added as a diluent to the raw material for forming a hard coat film. Organic solvents that can be used include butyl acetate, ethyl acetate, toluene, isopropanol and the like. Its usage is
The solid content concentration of the primer layer is preferably in the range of 1 to 50% by weight, and the solid content concentration of the hard coat film forming raw material is preferably 1 to 70% by weight, more preferably 3 to 30% by weight. preferable. If necessary, a leveling agent, an antistatic agent, a release agent, a matting agent, an inorganic filler and the like can be added to the raw material for forming a hard coat film.

In the present invention, characters and patterns can be formed on a part of the thermoplastic resin sheet by printing.

As a printing method, a conventionally known printing method such as gravure printing, lithographic printing, flexographic printing, dry offset printing, pad printing, screen printing and the like can be used according to the product shape and printing application.

As the composition of the printing ink used in printing, resin-based and oil-based can be used as main components, and natural resins such as rosin, Gilsonite, shellac, copearl, and phenol can be used as the resin-based. System and its derivatives, amino resin, butylated urea, melamine resin, polyester alkyd resin, styrene resin, acrylic resin, phenol resin, epoxy resin, polyamide resin, polycarbonate resin, saturated polyester resin, amorphous polyarylate resin, Amorphous polyolefin resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride
Synthetic resins such as vinyl acetate copolymer, butyral resin, methylcellulose resin, ethylcellulose resin, and urethane resin can be used. Particularly, when printing is performed on the surface of the first layer or the second layer on the interface side with the third layer, an ink component having high heat resistance is required. In such a case, a resin such as a polycarbonate resin or an amorphous resin is used. Preferable examples include polyarylate resins. In addition, a desired color can be adjusted by using a pigment or a dye in the printing ink.

On the other hand, as other surface treatments, a fluorine-based or water-repellent / oil-repellent coat, or a water immersion coat using a photocatalyst or the like can be used.

The method of mounting the thermoplastic resin sheet on the surface of the mold cavity and the surface of the mold core includes a method of applying static electricity to the thermoplastic resin sheet and mounting the thermoplastic resin sheet on the surface of the mold cavity and the surface of the core. A method of mounting the sheet on the cavity surface and core surface of the mold by suctioning the sheet from a suction groove provided in the mold by vacuum or the like, and performing a pre-drilling process on a gate portion or a tab portion of the thermoplastic resin sheet. The method of mounting using pins provided on the mold cavity surface or core surface, attaching iron pieces etc. to the tab part of the thermoplastic resin sheet, and embedding magnets in the mold cavity surface or core surface in advance Other conventionally known methods such as a mounting method can be used.

According to the present invention, the 2
(2) Injecting a transparent thermoplastic resin (hereinafter sometimes referred to as “resin b”) as a third layer into the space between the first layer and the second layer as the third layer with respect to the thermoplastic resin sheet.
Filling at an injection speed of 00 mm / sec or more is the second
(Hereinafter, may be referred to as “requirement (2)”). By performing molding that satisfies such conditions, even in a large molded product, a state having almost uniform distortion and heat history at the time of filling is secured, and optical distortion caused by these distributions and unevenness is eliminated, and such distortion is suppressed. It is possible to compress the filled resin in a state where the condition is solved.

In the requirement (2), more preferably 350
mm / sec or more, particularly preferably 400 mm / sec
That is all. The upper limit of the speed is about 800 mm / sec. In the range of 300 to 800 mm / sec, it is possible to achieve the object of the present invention and to obtain a good large-sized glazing product with little burnt on a molded product due to high speed.

In order to achieve an injection speed of 300 mm / sec or more, it is fundamental to increase the injection horsepower by increasing the capacity of the accumulator or increasing the horsepower of the motor. It is also necessary to optimize the structure of the injection cylinder, the hydraulic control system, the motor control system, etc., in order to achieve control and response of the screw speed and position at extremely high speed and short time. As such a system, various currently known methods can be used.

The power source may be a system using a hydraulic pump or a system using an electric motor (including a linear motor), but a system using a hydraulic pump is more preferable for large molded products. In addition, the injection device
In-line method by general plasticizing screw advance,
Any of the so-called pre-plaster systems in which a plasticizing screw and a plunger for filling are separate can be used.

On the other hand, on the surface of the mold, a mold having a sufficient gas vent groove so that gas can be smoothly vented from the mold, a porous sintered metal, a vacuum pump through a vent hole, or the like is used. A pressure-reducing device is preferably used.

Here, the injection speed means an average speed from the start to the end of the filling of the space mainly composed of the surface of the first layer and the surface of the second layer with the resin b, and is not necessarily a constant speed. It is not necessary, and molding with multiple injection speeds is also possible.

In the present invention, after the above-mentioned filling, (3) the compressive force is applied while cooling the multilayer structure molded product comprising the first layer, the second layer and the third layer until the molded product can be taken out of the mold. The third requirement is to make it act (hereinafter, may be referred to as “requirement (3)”). Due to such compression, a low-distortion molded product excellent in heat history balance and pressure balance particularly in the thickness direction in the requirement (1) and particularly in the in-plane direction in the requirement (2) can be used as it is as a desired molded product. It can be taken out of the mold.

On the other hand, in normal injection compression molding, compression is performed with a distribution already. Therefore, even if the compression itself is uniform, the pressure is concentrated on the portion where the solidified layer is formed quickly and hardened, and as a result, it is difficult to eliminate the distribution.

A preferable compression condition is a case where the molded article having a multilayer structure is compressed while the pressure difference in the mold between the vicinity of the gate and the vicinity of the end of the flow is 10 MPa or less. In order to satisfy such conditions, the start timing of the compression step, the compression stroke, that is, the initial cavity volume, the compression pressure, the compression time, and the like are determined. If the holding pressure applied during compression is excessively high, such a pressure difference is likely to occur. On the other hand, it is most appropriate to adjust the compression stroke (initial mold cavity volume) so that it is not necessary to apply excessive holding pressure.

With respect to the pressure difference in the mold, the value can be confirmed by disposing various pressure sensors at such positions. In addition, the vicinity of the gate here means
The mold cavity or mold core surface portion within 3 cm from the gate position is the standard. Similarly, the vicinity of the flow end is the mold cavity or the mold within 3 cm from the position corresponding to the flow end of the molded product. Refers to the surface of the mold core. It is more preferable that the above conditions can be satisfied in a portion as close as possible to the gate position and the flow end position.

The thickness difference between the thermoplastic resin sheets forming the first and second layers and the cylinder temperature during injection molding also affect the pressure difference in the mold. It is possible to control the pressure difference in the mold. In the present invention, if attention is paid to the amount of holding pressure and compression stroke, since the resin is in a substantially uniform state at the time of filling, the pressure difference in the mold during the subsequent compression is reduced by 10M.
It can be said that the degree of freedom for the condition within Pa is high.

The injection compression molding method used in the present invention includes:
For example, any of a clamping compression molding method using opening and closing of a platen (a plate on which a mold is mounted), a core compression molding method using a compression cylinder of a molding machine platen, a ball screw, and the like can be used.

The above-mentioned mold-clamping compression molding method means that the mold parting surfaces of the fixed side and the movable side are opened at a predetermined interval, resin is injected, and then the parting surface is pressed by the mold clamping force. Contact and compression. Further, the core compression molding method refers to means for bringing the respective parting surfaces of the mold into contact with each other during mold clamping before injection, injecting resin with a predetermined mold clamping force, and then compressing the resin. In the step of compressing after injection, the movable core is advanced and compressed in a direction in which the volume of the cavity is reduced by a compression mechanism installed in a molding machine, a mold, or the like. Examples of the compression mechanism include a compression cylinder and a ball screw. In the present invention, the core compression molding method can be cited as a more preferable method because it enables more uniform compression.

The mold temperature in the present invention is preferably lower than the glass transition temperature of such a thermoplastic resin sheet, and more preferably such a glass transition temperature, so as not to give unnecessary softening or deformation to the thermoplastic resin sheet. 1 than
The case where the temperature is lower than 0 ° C., more preferably the case where the temperature is lower than 20 ° C. When different resin sheets are mounted on the surface of the mold cavity and the surface of the mold core, it is possible to set the mold temperature according to the respective temperatures, but from the viewpoint of molding stability, It is preferred to adjust for a low glass transition temperature.

On the other hand, in order to obtain a molded article having good optical distortion, it is necessary that cooling after filling with the resin b is mild. In the present invention, the thermoplastic resin sheet has a suitable heat insulating effect, and thus has an advantageous condition in such a point. However, even in such a case, the condition of the mold temperature is an important factor.

Therefore, when the glass transition temperature of the resin b is Tg (° C.), the mold temperature in the present invention is preferably maintained at a temperature lower than Tg, more preferably [Tg-10]. (° C)-[Tg-100]
(° C.), more preferably [Tg-20] (° C.) to [Tg
-80] (° C), particularly preferably [Tg-20] (° C).
~ [Tg-50] (° C). On the other hand, molding can be performed sufficiently even when the Tg is higher than the resin b, but in such a case, the sheet layer can be formed at a low temperature and quickly molded. After cooling, it is necessary to take measures such as taking out the molded product. In addition, the glass transition temperature mentioned here is JIS.
It was measured by the method specified in K7121.

The molding method of the present invention for obtaining a molded article with little optical distortion can be used in combination with two-color molding, sandwich molding, gas assist molding and the like.

The polycarbonate resin which can be preferably used in the present invention is usually obtained by reacting a dihydric phenol with a carbonate precursor by an interfacial polycondensation method or a melt transesterification method. It has a viscosity average molecular weight of 10,000 to 40,000 obtained by polymerization by a solid phase transesterification method or a ring carbonate polymerization method of a cyclic carbonate compound, and preferably has a viscosity average molecular weight of 14,000 to 30,000. ,
More preferably, it is 16,000 to 25,000. In order to obtain a molded product with little optical distortion, a resin having a low melt viscosity and a good viscosity is desirable. However, if the viscosity is too low, the impact strength characteristic of a polycarbonate resin cannot be maintained.

The viscosity average molecular weight (M) mentioned here
Is the intrinsic viscosity [η] of the solution measured at 20 ° C. using methylene chloride as a solvent using an Ostwald viscometer,
It is determined from the following Schnell viscosity equation [η] = 1.23 × 10 ⁻⁴ M ^0.83 .

As the bisphenols for producing the polycarbonate resin, bisphenol A is particularly preferred, but there is no particular limitation on polycarbonate resins polymerized from other known phenols.

Representative examples of the dihydric phenol used here include hydroquinone, resorcinol, 4,4
4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-
Dimethyl) phenyl @ methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4
-Hydroxyphenyl) propane (commonly known as bisphenol A), 2,2-bis} (4-hydroxy-3-methyl)
Phenyl {propane, 2,2-bis {(4-hydroxy-3,5-dimethyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dibromo) phenyl}
Propane, 2,2-bis {(3-isopropyl-4-hydroxy) phenyl} propane, 2,2-bis} (4-
(Hydroxy-3-phenyl) phenyl} propane, 2,
2-bis (4-hydroxyphenyl) butane, 2,2-
Bis (4-hydroxyphenyl) -3-methylbutane,
2,2-bis (4-hydroxyphenyl) -3,3-dimethylbutane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2, 2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-
(Hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 1,1-bis (4-hydroxyphenyl)-
3,3,5-trimethylcyclohexane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy-3-methyl) phenyl} fluorene, α, α′-bis (4- Hydroxyphenyl) -o-
Diisopropylbenzene, α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α
α'-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy Diphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl ketone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl ester and the like, and these may be used alone or in combination of two or more. Can be mixed and used.

Among them, bisphenol A, 2,2-bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxyphenyl)-
3,3-dimethylbutane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4
A homopolymer obtained from at least one bisphenol selected from the group consisting of -hydroxyphenyl) -3,3,5-trimethylcyclohexane and α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, or Copolymers are preferred. In particular, bisphenol A homopolymer and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and bisphenol A, 2,2-bis {(4-hydroxy- Copolymers with 3-methyl) phenyl} propane or α, α′-bis (4-hydroxyphenyl) -m-diisopropylbenzene are preferably used.

As the carbonate precursor, carbonyl halide, carbonate ester or haloformate is used, and specific examples include phosgene, diphenyl carbonate, dihaloformate of dihydric phenol and the like.

In producing the polycarbonate resin by reacting the above-mentioned dihydric phenol with the carbonate precursor by the interfacial polycondensation method or the melt transesterification method, if necessary, a catalyst, a terminal stopper and an oxidation of the dihydric phenol may be carried out. An inhibitor or the like may be used. Further, the polycarbonate resin may be a branched polycarbonate resin obtained by copolymerizing a trifunctional or higher polyfunctional aromatic compound, or a polyester carbonate resin obtained by copolymerizing an aromatic or aliphatic bifunctional carboxylic acid, Further, a mixture of two or more of the obtained polycarbonate resins may be used.

Examples of the trifunctional or higher polyfunctional aromatic compound include phloroglucin, phloroglucid, and 4,6-
Dimethyl-2,4,6-tris (4-hydroxydiphenyl) heptene-2,2,4,6-trimethyl-2,4
6-tris (4-hydroxyphenyl) heptane, 1,
3,5-tris (4-hydroxyphenyl) benzene,
1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dimethyl-4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5-methylbenzyl) ) -4-Methylphenol, 4
-{4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene} -α, α-dimethylbenzylphenol and other trisphenols, tetra (4-hydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) )
Examples thereof include ketone, 1,4-bis (4,4-dihydroxytriphenylmethyl) benzene, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, and acid chlorides thereof, among which 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-
Tris (3,5-dimethyl-4-hydroxyphenyl)
Ethane is preferred, and 1,1,1-tris (4-hydroxyphenyl) ethane is particularly preferred.

When a polyfunctional compound producing such a branched polycarbonate resin is contained, such a ratio is preferably from 0.001 to 1 mol%, more preferably from 0.005 to 0.5 mol%, particularly preferably from the total amount of the aromatic polycarbonate. 0.01
~ 0.3 mol%. In addition, particularly in the case of the melt transesterification method, a branched structure may be generated as a side reaction, and the amount of such a branched structure is also 0.001 to 1 mol%, preferably 0.005 to 5 mol%, of the total amount of the aromatic polycarbonate.
0.5 mol%, particularly preferably 0.01 to 0.3 mol%
Is preferred. The ratio is ¹ H
-It can be calculated by NMR measurement.

The reaction by the interfacial polycondensation method is usually a reaction between dihydric phenol and phosgene, and is carried out in the presence of an acid binder and an organic solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used.
As the organic solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. Further, for promoting the reaction, for example, a catalyst such as a tertiary amine such as triethylamine, tetra-n-butylammonium bromide, or tetra-n-butylphosphonium bromide, a quaternary ammonium compound, or a quaternary phosphonium compound may be used. it can. At that time, the reaction temperature is usually 0 to 40 ° C., the reaction time is preferably about 10 minutes to 5 hours, and the pH during the reaction is preferably maintained at 9 or more.

In such a polymerization reaction, a terminal stopper is usually used. Monofunctional phenols can be used as such a terminal stopper. Monofunctional phenols are commonly used as molecular terminators for molecular weight control, and the resulting polycarbonate resins are capped by groups based on monofunctional phenols, so that Excellent heat stability. Such a monofunctional phenol is generally a phenol or a lower alkyl-substituted phenol, and may be a monofunctional phenol represented by the following general formula (1).

[0058]

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(Wherein A is a hydrogen atom or a carbon number of 1 to 9)
Is a linear or branched alkyl group or a phenyl group-substituted alkyl group, and r is an integer of 1 to 5, preferably 1 to 3. Specific examples of the above monofunctional phenols include, for example, phenol, p-tert-butylphenol, p-cumylphenol and isooctylphenol.

Further, other monofunctional phenols include:
Phenols or benzoic acid chlorides having a long-chain alkyl group or aliphatic polyester group as a substituent, or long-chain alkylcarboxylic acid chlorides can also be used. Among these, phenols having a long-chain alkyl group represented by the following general formulas (2) and (3) as a substituent are preferably used.

[0061]

Embedded image

[0062]

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(Wherein X is -RO-, -R-CO-O
— Or —RO—CO—, wherein R represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 10, preferably 1 to 5 carbon atoms, and n represents an integer of 10 to 50. Show. )

The substituted phenols of the general formula (2) are preferably those having n of 10 to 30, especially 10 to 26, and specific examples thereof include decylphenol, dodecylphenol, tetradecylphenol, hexadecylphenol and Octadecylphenol, eicosylphenol, docosylphenol, triacontylphenol and the like can be mentioned.

As the substituted phenols of the general formula (3), compounds wherein X is -R-CO-O- and R is a single bond are suitable, and n is 10-30, especially 10-26.
Are preferred, and specific examples thereof include, for example, decyl hydroxybenzoate, dodecyl hydroxybenzoate,
Examples include tetradecyl hydroxybenzoate, hexadecyl hydroxybenzoate, eicosyl hydroxybenzoate, docosyl hydroxybenzoate and triacontyl hydroxybenzoate.

It is desirable that the terminal terminator is introduced at least at 5 mol%, preferably at least 10 mol%, based on all terminals of the obtained polycarbonate resin. More preferably, the terminal terminator is introduced in an amount of 80 mol% or more with respect to all terminals, that is, the terminal hydroxyl group (OH group) derived from dihydric phenol is more preferably 20 mol% or less, and particularly preferably. This is the case when 90 mol% or more of the terminal terminator is introduced to all the terminals, that is, when the OH group is 10 mol% or less. Further, the terminal stoppers may be used alone or in combination of two or more.

The reaction by the melt transesterification method is usually a transesterification reaction between a dihydric phenol and a carbonate ester, and is produced by mixing the dihydric phenol with the carbonate ester while heating in the presence of an inert gas. It is performed by a method of distilling alcohol or phenol. The reaction temperature varies depending on the boiling point of the produced alcohol or phenol, but is usually in the range of 120 to 350 ° C. In the late stage of the reaction, the system was adjusted to 1.33 × 10 ³ -1.
The alcohol or phenol produced by reducing the pressure to about 3.3 Pa is easily distilled. Reaction time is usually 1-4
About an hour.

Examples of the carbonate ester include an optionally substituted ester such as an aryl group having 6 to 10 carbon atoms, an aralkyl group or an alkyl group having 1 to 4 carbon atoms. Specifically, diphenyl carbonate, bis (chlorophenyl) carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate and the like can be mentioned, with diphenyl carbonate being preferred.

A polymerization catalyst can be used to increase the polymerization rate. Examples of the polymerization catalyst include sodium hydroxide, potassium hydroxide, alkali metal compounds such as sodium and potassium salts of dihydric phenol, and water. Alkaline earth metal compounds such as calcium oxide, barium hydroxide and magnesium hydroxide; nitrogen-containing basic compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylamine and triethylamine; alkoxides of alkali metals and alkaline earth metals Manganese, organic acid salts of alkali metals and alkaline earth metals, zinc compounds, boron compounds, aluminum compounds, silicon compounds, germanium compounds, organic tin compounds, lead compounds, osmium compounds, antimony compounds Compounds, titanium compounds, usually the esterification reaction, such as zirconium compounds, there can be used a catalyst used in the transesterification reaction. The catalyst may be used alone or in combination of two or more. The amount of the polymerization catalyst used is preferably 1 × 10 ⁻⁸ to 1 ×, based on 1 mol of the dihydric phenol used as the raw material.
It is selected in the range of 10 ⁻³ equivalents, more preferably 1 × 10 ^{−7 to} 5 × 10 ⁻⁴ equivalents.

In the polymerization reaction, in order to reduce the number of phenolic terminal groups, for example, bis (chlorophenyl) carbonate, bis (bromophenyl) carbonate, bis (nitrophenyl) carbonate is used later or after completion of the polycondensation reaction. , Bis (phenylphenyl)
Carbonate, chlorophenylphenyl carbonate,
It is preferable to add compounds such as bromophenylphenyl carbonate, nitrophenylphenyl carbonate, phenylphenyl carbonate, methoxycarbonylphenylphenyl carbonate, and ethoxycarbonylphenylphenyl carbonate. Of these, 2-chlorophenylphenyl carbonate, 2-methoxycarbonylphenylphenyl carbonate and 2-ethoxycarbonylphenylphenyl carbonate are preferred, and 2-methoxycarbonylphenylphenyl carbonate is particularly preferred.

Further, in the melt transesterification method, it is desirable to neutralize the activity of the catalyst remaining after polymerization by using a deactivator. Examples of such a deactivator include benzenesulfonic acid, p-toluenesulfonic acid, methylbenzenebenzenesulfonate, ethylbenzenebenzenesulfonate, butylbenzenesulfonate, octylbenzenesulfonate, phenylbenzenesulfonate, methyl p-toluenesulfonate, p-toluenesulfonate -Sulfonic esters such as ethyl toluenesulfonate, butyl p-toluenesulfonate, octyl p-toluenesulfonate, phenyl p-toluenesulfonate;
Trifluoromethanesulfonic acid, naphthalenesulfonic acid, sulfonated polystyrene, methyl acrylate-sulfonated styrene copolymer, 2-phenyl-2-propyl dodecylbenzenesulfonic acid, 2-phenyl-2-butyl dodecylbenzenesulfonic acid, Tetrabutylphosphonium octylsulfonate, tetrabutylphosphonium decylsulfonate, tetrabutylphosphonium benzenesulfonate, tetraethylphosphonium dodecylbenzenesulfonate, tetrabutylphosphonium dodecylbenzenesulfonate, tetrahexylphosphonium dodecylbenzenesulfonate, Dodecylbenzenesulfonic acid tetraoctyl phosphonium salt, decyl ammonium butyl sulfate, decyl ammonium decyl sulfate, Silammonium methyl sulfate, dodecyl ammonium ethyl sulfate, dodecyl methyl ammonium methyl sulfate, dodecyl dimethyl ammonium tetradecyl sulfate, tetradecyl dimethyl ammonium methyl sulfate, tetramethyl ammonium hexyl sulfate, decyl trimethyl ammonium hexadecyl sulfate, tetrabutyl ammonium dodecyl benzyl sulfate, Examples include compounds such as tetraethylammonium dodecylbenzyl sulfate and tetramethylammonium dodecylbenzyl sulfate, but are not limited thereto, and two or more of these compounds may be used in combination.

Among them, phosphonium salts or ammonium salts are preferred. The amount of such a catalyst is preferably 0.5 to 50 mol per 1 mol of the remaining catalyst, and 0.01 to 500 ppm, more preferably 0 to 500 ppm, based on the polycarbonate resin after polymerization. 0.01 to 300 ppm, particularly preferably 0.01 to 300 ppm
Used at a rate of 100 ppm.

The transparent thermoplastic resin forming the first layer, the second layer and the third layer of the present invention can contain a release agent, and this can suppress the distortion at the time of release. Gives favorable results in terms of: As the release agent, a saturated fatty acid ester is generally used, for example, monoglycerides such as stearic acid monoglyceride, polyglycerin fatty acid esters such as decaglycerin decastearate and decaglycerin tetrastearate, and lower fatty acids such as stearic acid stearate. Esters, higher fatty acid esters such as sebacic behenate, and erythritol esters such as pentaerythritol tetrastearate are used. The release agent is 0.0% per 100 parts by weight of the thermoplastic resin.
1 to 1 part by weight is used.

Further, if necessary, a phosphorus-based heat stabilizer represented by a phosphite is added to the first layer, the second layer,
And 0.001 to 0.1 part by weight per 100 parts by weight of the transparent thermoplastic resin forming the third layer. Examples of the phosphorus-based heat stabilizer include trimethyl phosphate, triphenyl phosphate, tris (nonylphenyl) phosphite, triphenyl phosphite, and tris (2,4-
Di-tert-butylphenyl) phosphite, bis-
(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol-di-phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol-di-phosphite, tris (ethylphenyl) Phosphite, tris (butylphenyl) phosphite and tris (hydroxyphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4′-biphenylenediphosphonite, tetrakis (2,4-diphenyl) -Tert-butylphenyl) -4,
3'-biphenylenediphosphonite, tetrakis (2,
4-di-tert-butylphenyl) -3,3′-biphenylenediphosphonite, bis (2,4-di-tert)
-Butylphenyl) -4-biphenylenediphosphonite and the like are preferred.

For the purpose of improving weather resistance and cutting off harmful ultraviolet rays, the transparent thermoplastic resin forming the first, second and third layers of the present invention may further contain an ultraviolet absorber. Can be. As such an ultraviolet absorber, for example, a benzophenone-based ultraviolet absorber represented by 2,2'-dihydroxy-4-methoxybenzophenone; for example, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5 -Chlorobenzotriazole, 2
-(3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2,2'-
Methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl)
Phenol], 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole and 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzo Benzotriazole ultraviolet absorbers represented by triazole are exemplified, and these may be used alone or in combination of two or more. Among these ultraviolet absorbers, benzotriazole-based ultraviolet absorbers are preferred.

The transparent thermoplastic resin forming the first layer, the second layer and the third layer of the present invention may have a blue color in order to cancel the yellow tint based on the thermoplastic resin itself or the blending of the ultraviolet absorbent. Ingredients can be included. As the bluing agent, any one can be used without any particular difficulty as long as it is used for a thermoplastic resin. It is particularly useful for polycarbonate resins. As a specific bluing agent, for example, the common name Solvent Viol
et13 [CA. No (color index No) 60
725; Trade name "Macrolex Violet B" manufactured by Bayer, "Diaresin Blue G" manufactured by Mitsubishi Chemical Corporation, "Sumiplast Violet B" manufactured by Sumitomo Chemical Co., Ltd.], generic name Solvent Violet 31
[CA. No. 68210; Trade name “Diaresin Violet D” manufactured by Mitsubishi Chemical Corporation], generic name Solve
nt Violet 33 [CA. No. 60725; Trade name “Diaresin Blue J” manufactured by Mitsubishi Chemical Corporation], generic name Solvent Blue 94 [CA. No615
00; trade name “Diaresin Blue N” manufactured by Mitsubishi Chemical Corporation], generic name Solvent Violet 36 [C
A. No. 68210; trade name "Macrolex Violet 3R" manufactured by Bayer AG], generic name SolventBl
ue97 [trade name “Macrolex Blue RR” manufactured by Bayer AG] and generic name Solvent Blue 45
[CA. No. 61110; Trade name "Tetrazol Blue RLS" manufactured by Sando Co., Ltd.], Macrolex Violet and Triazole Blue RLS manufactured by Ciba Specialty Chemicals, etc., and Macroxol Violet and Triazole Blue RLS are particularly preferable.

In the present invention, by using the above-mentioned specific molding method, a large glazing product can be efficiently produced by injection molding. Particularly, it is suitable for a large-sized molded product in which the maximum distance from the gate portion to the flow end portion is 200 mm or more.

Further, according to the present invention, the angle between the normal of the molded product surface and the normal of the projection surface was measured according to JIS R3212, which was not obtained by the conventional injection molding method. Is less than 1.5 minutes and the maximum distance from the gate to the flow end is 20 minutes.
A plate-shaped molded product having a thickness of 0 mm or more is provided. In addition, such a plate-shaped molded product includes not only a flat shape but also a shape having a curved surface.

The molded article is specifically useful for glazing materials for vehicles, for example, windows of various automobiles, roofs and windows of motorcycles, bicycles and automatic walkers, windows of construction machines, and the like.

[0080]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples. The thermoplastic resins used in the examples are as follows (hereinafter, abbreviated to PC and PCS, respectively). (Transparent thermoplastic resin forming the third layer) PC: 100 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 18,500 prepared from bisphenol A and phosgene by a conventional method, and Sandstab P-EPQ
A pellet-like polycarbonate resin composition obtained by blending 0.03 parts by weight (manufactured by Sandoz) and 0.2 parts by weight of glycerin monostearate and melt-extruding at 280 ° C. In addition, in a flat molded product having a thickness of 2 mm obtained by injection molding such a resin at 280 ° C., JIS
Haze measured according to standard K7105 is 0.7%
Met.

(Transparent thermoplastic resin sheet forming first layer and second layer) PCS: Viscosity average molecular weight 25,000, thickness 0.5 mm, prepared from bisphenol A and phosgene by a conventional method.
The polycarbonate resin sheet obtained by the T-die extrusion method. Such a sheet is coated with a silicone resin-based hard coat according to the following procedure. The sheet has a perspective distortion amount of 1.2 minutes in a measuring method shown in the following ((1) Optical distortion characteristics). The polycarbonate resin is
The haze obtained by injection molding at 80 ° C. was 0.6%.

(Hard Coat Treatment Method) A flask equipped with a reflux condenser and a stirrer was charged with 70 parts of methyl methacrylate (hereinafter abbreviated as MMA) and 39 parts of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA) in a flask purged with nitrogen. , Azobisisobutyronitrile (hereinafter AIB)
0.18 parts) and 200 parts of 1,2-dimethoxyethane were added, mixed and dissolved. Then, the reaction was carried out in a nitrogen stream at 70 ° C. for 6 hours with stirring. The obtained reaction solution was added to n-hexane and purified by reprecipitation, and MMA / HE
90 parts of a copolymer (acrylic resin (I)) having a MA composition ratio of 70/30 (molar ratio) was obtained. The weight average molecular weight of the copolymer was measured by GPC (column; Shodex GP).
From CA-804, eluent; THF), it was 80,000 in terms of polystyrene.

Further, methyltrimethoxysilane 142
Parts, 72 parts of distilled water and 20 parts of acetic acid were mixed under cooling with ice water,
The mixture was stirred at 25 ° C. for 1 hour and diluted with 116 parts of isopropanol to obtain 350 parts of a solution (X) of a hydrolyzed condensate of methyltrimethoxysilane. On the other hand, 208 parts of tetraethoxysilane and 81 parts of 0.01 N hydrochloric acid are mixed under cooling with ice water, the mixture is stirred at 25 ° C. for 3 hours, diluted with 11 parts of isopropanol, and a solution of the hydrolyzed condensate of tetraethoxysilane ( Y) 300 parts were obtained.

Next, as the composition for the first layer of the hard coat,
8 parts of the acrylic resin (I) is methyl ethyl ketone 40
Parts, methyl isobutyl ketone 20 parts, ethanol 5.2
, 14 parts of isopropanol and 10 parts of 2-ethoxyethanol, and then dissolved in a solution of the hydrolyzed condensate of methyltrimethoxysilane (X).
10 parts were added and stirred at 25 ° C. for 5 minutes, and the solution was further added to a melamine resin (Cymel 3 manufactured by Mitsui Cytec Co., Ltd.).
03) 1 part was added and the mixture was stirred at 25 ° C for 5 minutes to prepare a coating composition (i).

Further, as the composition for the second layer of the hard coat,
Water-dispersed colloidal silica dispersion (Nissan Chemical Industries, Ltd.)
Made Snowtex 30 solid content concentration 30% by weight) 10
To 12 parts of distilled water and 20 parts of acetic acid were added and stirred.
4 parts were added. This mixture was stirred at 25 ° C. for 1 hour. To the reaction mixture obtained, 20 parts of a tetraethoxysilane hydrolyzed condensate solution (Y) and 1 part of sodium acetate as a curing catalyst were added, diluted with 200 parts of isopropanol, and coated. Composition (ii) was prepared.

The coating composition (i) was applied to one surface of a 0.5 mm thick PC resin sheet with a wire bar, allowed to stand at 25 ° C. for 20 minutes, and thermally cured at 120 ° C. for 30 minutes. The thickness of the first layer was 2.5 μm. Then
Coating composition (ii) on the coating surface of the sheet
Is further applied with a wire bar, and allowed to stand at 25 ° C. for 20 minutes.
Heat cured at 120 ° C. for 2 hours. The thickness of the second layer is 5.0
μm.

The evaluation was performed according to the following method. (1) Optical distortion characteristics The amount of perspective distortion was measured in the following manner in accordance with JIS R3212. Set the necessary slides on a slide projector (AF250 manufactured by Cabin Kogyo Co., Ltd.)
m, a large number of circles having a center-to-center distance of 24 mm from the circle arranged in a line were projected. The projection was performed at a distance of 4 m from the slide projector to the plate-shaped molded product (in the case of a sheet), and at a distance of 4 m from the slide projector to the projection surface. The molded product was held in a jig so that the periphery of the molded product was sandwiched by 10 mm each, and the molded product was set so that the angle between the normal to the projection surface and the normal to the molded product was 55 °. The diameter of the ellipse on which the circle was projected as a distorted ellipse was measured with a digital caliper in units of 0.1 mm, and the amount of perspective distortion was calculated from the calculation formula from the largest diameter of the projected ellipse. (2) Maximum pressure difference As shown in FIG. 3, the pressure was recorded on a recorder using a strain gauge type pressure sensor in contact with the surface of the mold cavity and the surface of the core. The maximum value was measured.

Example 1 Injection compression molding die equipped with an ultra-high speed injection device capable of achieving an injection speed of 600 mm / sec after drying PC at 120 ° C. for 5 hours, and a core compression mechanism using a hydraulic cylinder. Injection molding machine with equipment (FN-8000-36ATN manufactured by Nissei Plastic Industry Co., Ltd.)
The molded article shown in FIGS. 1 and 2 was molded at a cylinder temperature of 300 ° C. This molded product is 235m long
A plate-shaped molded product having a size of mx 180 mm in width x 5 mm in thickness and having a film gate (gate portion thickness 1.5 mm) was used (see Fig. 2). The mold temperature was kept at 105 ° C. using a mold temperature controller.

As shown in FIG. 3, the PCS is mounted on the mold cavity surface and the mold core surface by using static electricity in the mold so that the hard coat side is in contact with the mold surface.
The PC was filled at an injection speed of 350 mm / sec. At that time, before the injection, the movable core is retracted by 1 mm (the distance between the mold cavity surface and the core surface is about 6 mm), and then the resin is filled between the first and second layer sheets. The movable core was compressed at an average speed of 0.05 mm / sec. During the compression process, a pressure of 100 MPa was applied to the resin. Under such conditions, the pressure difference in the mold is 6 MPa
It was stable before and after without exceeding 10 MPa. After the cooling was completed, the molded product was taken out, and the molding cycle was 95 seconds. The optical distortion characteristics of the thus obtained molded product were evaluated. Table 1 shows the evaluation results.

[Examples 2 to 4, Comparative Examples 1 to 5] Example 1
Example 1 except that various conditions described in Table 1 and Table 1 were changed.
The procedure was performed under the same conditions as described above. In the case of molding without the thermoplastic resin sheet attached, the capacity was increased in a proportionate manner in such a manner, and the core receding amount was reduced by the amount of the sheet. That is, when the sheet is mounted on both the cavity and the core surface, the retreat amount is reduced by 1 mm, and when only one of the sheets is mounted, the retreat amount is 0.5 mm.
Such temperature measurement was performed by the method of making the temperature smaller.

[0091]

[Table 1]

As is evident from Table 1, when all three of these conditions are satisfied, as compared with the case where no sheet is mounted, the case where the injection speed is less than a certain amount, and the case where no compressive force is applied, etc. It can be seen that a low-distortion molded product having a very good amount of perspective distortion was obtained in such a large molded product. It can also be seen that particularly good molded bodies can be obtained when the maximum pressure difference during molding is smaller than in the examples.

[0093]

According to the present invention, it is possible to obtain an optical product having an excellent optical distortion characteristic, and particularly to an application requiring an excellent optical distortion characteristic, such as an automobile glazing product in the automobile field. Very suitable.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing an outline of a plate-like molded body.

FIG. 2 is a side view schematically showing an outline of a gate portion of the plate-shaped molded body.

FIG. 3 is a schematic view of a mold structure as viewed from the side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Plate-shaped molded product main body 2 Plate-shaped molded product gate part (width: 180 mm) 3 Plate-shaped molded product runner part (width 195 mm) 4 Plate-shaped molded product width (180 mm) 5 Plate-shaped molded product length (235 mm) 6 Sprue part 7 Pressure sensor corresponding to the gate part (FIG. 1 shows a part corresponding to the mounting position) 8 Pressure sensor corresponding to the flow end part (FIG. 1 shows a part corresponding to the mounting position) 9 Runner part thickness (5 mm) 10 Runner length (14 mm) 11 Maximum sprue diameter (8 mm) 12 Sprue length (100 mm) 13 Gate length (7 mm) 14 Gate thickness (1.5 mm) 15 Gate entrance width (1.5 mm) 16 Plate-shaped product Thickness (5 mm) 17 Fixed-side mold 18 Movable-side mold 19 Temperature sensor embedded portion of main mold 20 Movable core 21 Compression operation of movable core 22 Thermoplastic resin sheet mounted on mold cavity surface 23 Thermoplastic resin sheet mounted on mold core surface 24 Filled resin

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B29L 9:00 B29L 9:00

Claims (7)

[Claims] 1. A method for obtaining a molded article having a multilayer structure with little optical distortion, comprising: (1) a transparent thermoplastic resin having a first layer on a surface of a mold cavity and a second layer on a surface of a mold core; (2) The first resin sheet is attached.
A space between the layer and the second layer is filled with a transparent thermoplastic resin (hereinafter, sometimes referred to as “resin b”) as a third layer at an injection speed of 300 mm / sec or more, and (3)
A multilayer structure having little optical distortion characterized in that a compressive force is applied while cooling the multilayer structure molded product comprising the first layer, the second layer and the third layer until the molded product can be taken out of the mold. A molding method for obtaining molded articles. 2. The molding method according to claim 1, wherein the thickness of the transparent thermoplastic resin sheet forming the first layer and the second layer is 200 to 500 μm. 3. When compressing a multilayered molded product in a mold,
The pressure difference in the mold between the vicinity of the gate and the end of the flow is 10
The molding method for obtaining a molded article having a small optical distortion according to claim 1, wherein the molding pressure is not more than MPa. 4. The resin (b) has a viscosity average molecular weight of 10,000.
2. Polycarbonate resin of up to 40,000.
4. A molding method for obtaining a molded article having a small optical distortion according to any one of items 3 to 3. 5. The transparent thermoplastic resin sheet forming the first layer and the second layer has a viscosity average molecular weight of 10,000-4.
The molding method for obtaining a molded product having a small optical distortion according to any one of claims 1 to 4, which is a sheet made of polycarbonate resin of 000. 6. A molded article obtained by the molding method according to claim 1, wherein the maximum distance from the gate to the flow end is at least 200 mm. 7. The angle measured between the normal to the molded product surface and the normal to the projection surface is 5 in accordance with JIS R3212.
The perspective distortion amount at 5 ° is 1.5 minutes or less, and the maximum distance from the gate to the flow end is 200 mm.
The plate-shaped injection molded product described above.