JP2943183B2 - Laminated molding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a laminate formed of a steel sheet and a polyester film.

[Problems to be solved by conventional technology and invention]

Biaxially oriented polyester films are excellent in various mechanical properties, and their use has been attempted in various applications.

For example, it has been attempted to laminate a polyester film on a steel plate and use it as a refrigerator door. However, the polyester film is inferior in moldability at a curved surface portion, peels and cracks occur, and has not been put to practical use.

[Means for solving the problem]

In view of the above problems, the present inventors have conducted intensive studies,
The inventors have found that a laminate of a polyester film having specific physical properties and a steel sheet is an excellent molded product, and have completed the present invention.

That is, the gist of the present invention is that the strength at 100% elongation F ₁₀₀ is 0.5 to 5.0 kg / mm ² under the atmosphere of 150 ° C., and the plane orientation degree ΔP is 0.
It is in a molded product obtained by laminating a steel plate on a biaxially oriented polyester film having a thickness in the range of 050 to 0.110 and a thickness unevenness of 40% or less.

 Hereinafter, the present invention will be described in detail.

The polyester used in the present invention includes, as a dicarboxylic acid component, known terephthalic acid, oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenylether dicarboxylic acid, etc. Of one or more dicarboxylic acids of the formula (I), and as a diol component, ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycol, 1,4-cyclohexane It is a polyester comprising one or more known diol components such as dimethanol and neopentyl glycol.

In the polyester of the present invention, copolymerizable components include, for example, oxycarboxylic acids such as p-oxybenzoic acid, monofunctional compounds such as benzoic acid, benzoylbenzoic acid, and methoxypolyalkylene glycol; and polyfunctional compounds such as glycerin and pentaerythritol. Functional compounds can also be used to the extent that the product can retain a substantially linear polymer.

In the polyester constituting the molded article of the present invention, the proportion of polyethylene terephthalate is preferably 50 mol%.
It is more preferably at least 70 mol%. If the polyethylene terephthalate content is less than 50 mol%, the strength and heat resistance of the film are undesirably reduced.

The polyester constituting the molded article of the present invention contains an aliphatic dicarboxylic acid component in the acid component in an amount of usually 1 to 20 mol%, preferably 1 to 10 mol%. As the aliphatic dicarboxylic acid component, an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms, preferably 6 to 12 carbon atoms is preferable in view of moldability, heat resistance, and improvement in thickness unevenness.

On the other hand, a film in which a plasticizer or the like is not detected by NMR or the like when a 5 g film is extracted for 24 hours in boiling chloroform is preferable. If the plasticizer is mixed, it acts as a release agent and may cause a decrease in adhesiveness.

In addition, in order to improve the lubricity of the film, it is also preferable to include fine particles such as an organic lubricant and an inorganic lubricant. If necessary, a stabilizer, a coloring agent, an antioxidant, an antifoaming agent, and an antistatic agent are used. It may contain an additive such as an agent. As the fine particles imparting lubricating properties, known inert external particles such as kaolin, clay, calcium carbonate, silicon oxide, calcium terephthalate, aluminum oxide, titanium oxide, calcium phosphate, lithium fluoride, carbon black, and melting of polyester resin Internal particles formed inside the polymer during polyester production by a high melting point organic compound which is insoluble during film formation, a crosslinked polymer, and a metal compound catalyst used during polyester synthesis, such as an alkali metal compound or an alkaline earth metal compound. The content of the fine particles contained in the film is usually
0.002 to 0.9% by weight, and the average particle size is 0.001 to
Preferably it is in the range of 3.5 μm.

The polyester of the present invention has an intrinsic viscosity in the film of preferably 0.50 or more, more preferably 0.60 or more. If the intrinsic viscosity of the film is less than 0.50, it is not preferable because sufficient strength and moldability cannot be obtained.

In the film constituting the molded article of the present invention,
Film strength F ₁₀₀ at 100% elongation under atmosphere is
It is necessary to be in the range of 0.5 to 5.0 kg / mm ² (note that
It will be described later method of measuring the F _100).

F _{100 in the} present invention is the average value of the strength in the longitudinal and transverse directions of the film at 100% elongation at 150 ° C. F ₁₀₀ value is preferably 0.5~3.0kg / mm ^2, more preferably 0.5~2.0kg / m
m ² .

According to our study results, the intensity F ₁₀₀ value is deeply related to the formability of the film, the film F ₁₀₀ Kos to 5 kg / mm ^2, the moldability decreases, unfavorably. Also, F ₁₀₀
If the film is less than 0.5 kg / mm ² , the film will be deformed unevenly during molding, which is not preferable.

The difference in film strength between the longitudinal and transverse directions at 150 ° C. and 100% elongation is usually 3 kg / mm ² or less, preferably 2 kg / m 2.
m ² or less, more preferably 1 kg / mm ² . The difference is 3kg
If it exceeds / mm ² , the anisotropy becomes large and the moldability deteriorates.

In the film constituting the molding squad of the present invention, the unevenness of the thickness of the film is at most 40%, preferably at most 30%. If the thickness unevenness exceeds 40%, the moldability and the elongation of the film at the time of molding become non-uniform, and when integrally molded with metal, breakage or delamination may occur.

Film constituting the molded body of the present invention are F ₁₀₀ is an essential component that is in the above range, further planar orientation ΔP in the range of 0.050 to 0.110 of the film of the present invention, preferably 0.060
It is in the range of ~ 0.100. A film having a degree of plane orientation ΔP of more than 0.110 is not preferable because the moldability is insufficient. On the other hand, a film having a degree of plane orientation ΔP of less than 0.050 is not preferred because the strength of the film decreases and the flatness deteriorates.

Furthermore, the average refractive index of the film constituting the molded article of the present invention is preferably in the range of 1.570 to 1.595. Is 1.
If the film exceeds 595, the crystallinity of the film increases, which is not preferable. On the other hand, in the case of a film having a molecular weight of less than 1.570, on the contrary, the crystallization of the film is not sufficient, and the heat resistance is inferior.

The density of the film constituting the molded article of the present invention is preferably in the range of 1.345 to 1.390, more preferably 1.355 to 1.380. Films having a density of less than 1.345 are inferior in heat resistance and are not sufficient, while films having a density of more than 1.390 are not preferable because the moldability is insufficient.

The heat of fusion of the film constituting the molded article of the present invention is preferably in the range of 1 to 8 cal / g, more preferably 1 to 6 cal / g. Films having a heat of fusion of more than 8 cal / g are not preferred because moldability decreases. On the other hand, a film having a heat of fusion of less than 1 cal / g is extremely difficult to crystallize in a raw material drying step at the time of film formation, particularly when recycling ears and the like.
A complicated process such as vacuum drying is required, which is not preferable.
It is not preferable because the unevenness in the thickness of the film also worsens.

Regarding the shrinkage characteristics of the film constituting the molded article of the present invention, the shrinkage in both the longitudinal and transverse directions after treatment at 150 ° C. for 3 minutes is preferably 10% or less, more preferably 5% or less.
% Or less.

A film having a shrinkage ratio of more than 10% in the vertical or horizontal direction is not preferable because the film shrinks greatly in a heating section during the processing step.

Regarding the mechanical strength of the film constituting the molded article of the present invention, the Young's modulus in the machine direction and the transverse direction of the film is preferably 300 kg / mm ² or more, more preferably 350 kg / mm ² or more. A film having a Young's modulus of less than 300 kg / mm ² is not preferred because the film tends to elongate in the forming step.

Further, in the film of the present invention, the birefringence of the film is preferably 0.025 or less, more preferably 0.020 or less, if the birefringence of the film exceeds 0.025, the anisotropy of the film increases, the moldability. It is not preferable because it decreases.

The thickness of the film constituting the molded article of the present invention is not particularly limited, but preferably used thickness is 5 to 500 μm,
More preferably, it is 5 to 300 μm.

Next, a method for producing a film constituting the molded article of the present invention will be specifically described, as long as the constitutional requirements of the present invention are satisfied.
It is not particularly limited to the following examples.

The polyester of the present invention containing an appropriate amount of inorganic particles and the like as a slipping agent, if necessary, is dried using a commonly used dryer or vacuum dryer such as a hopper dryer, a paddle dryer, and an oven. And extrude. At the time of extrusion, any existing method such as a T-die method and a tubular method may be employed.

After the extrusion, the amorphous sheet is quenched to obtain an amorphous sheet. However, it is preferable to use an electrostatic application method during the quenching because unevenness in the thickness of the amorphous sheet is improved.

Then, the obtained amorphous sheet is stretched in the longitudinal and transverse directions so that the area magnification is at least 6 times, preferably 8 times or more, more preferably 8 times or more and 16 times or less to obtain a biaxially oriented film. After re-stretching the film in the machine direction and / or transverse direction according to the above, heat treatment is preferably performed at a temperature in the range of 150 to 200 ° C. to obtain a desired film.

In the heat treatment step, the transverse direction and / or the temperature at the highest temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet.
Alternatively, performing a relaxation of 0.1 to 30% in the longitudinal direction is also a preferred embodiment in the present invention. In particular, it is preferable to perform 5 to 30% relaxation in the horizontal direction. In the heat treatment step, a two-step heat treatment may be performed.

During or after the stretching step, in order to impart adhesiveness, antistatic property, slipperiness, mold release property, etc. to the film, a coating layer is formed on one or both surfaces of the film, or a corona discharge treatment or the like is performed. It does not matter. In particular, since a large area is laminated, antistatic easy adhesion is required.

The film thus obtained is printed, if necessary, further vapor-deposited, top-coated on the other surface, and the film is bonded to a steel plate via an adhesive.
Further, if necessary, the steel sheet and the film may be bonded via a PVC, an ABS, a polyolefin film or the like. An integrated product with the steel sheet thus obtained is subjected to drawing to obtain a product having a desired shape.

Such a molded article can be suitably used, for example, for a refrigerator door.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to Examples.
The present invention is not limited to these examples unless it exceeds the gist.

 In addition, the evaluation method of a film is shown below.

(1) Film strength at 100% elongation in an atmosphere of 150 ° C. F ₁₀₀ (kg / mm ² ) Intesco 20 tensile tester with a thermostatic chamber manufactured by Intesco Corporation
A 01-type thermostat was set at 150 ° C., a film having a width of 15 mm was set so that the distance between the chucks was 50 mm, and the film was allowed to stand for 2 minutes. Then, the strength at the time of 100% elongation at a tensile speed of 200 mm / min was measured. Measurements performed on longitudinal and transverse directions of the film, and the average value was defined as the F _100. In addition, about the film which fracture | ruptures before 100% extension, it converted according to the following formula.

(2) Film thickness unevenness The film thickness was measured at a length of 5 m along the longitudinal direction of the film using a continuous film thickness measuring device manufactured by Anritsu Electric Co. (using an electronic micrometer), and the thickness unevenness was calculated by the following formula. .

(3) Average refractive index (), degree of plane orientation (Δ
P), birefringence (Δn) The refractive index of the film was measured using an Abbe refractometer manufactured by Atago Co., and using a sodium lamp as a light source.

In the above formula, n _γ , n _β and n _α represent the maximum refractive index in the film plane, the refractive index in a direction perpendicular to the maximum refractive index, and the refractive index in the thickness direction, respectively.

(4) Heat of fusion of film (cal / g) Using a differential scanning calorimeter DSC-1B manufactured by PerkinElmer, the peak area accompanying the melting of the result of the sample measured at a heating rate of 16 ° C./min was obtained. It was calculated according to the following equation.

A: Heat of fusion per unit area on the chart when measuring indium under the same conditions (cal / cm ² ) S: Area of melting peak of sample (cm ² ) m: Sample and weight (g) (5) Intrinsic viscosity (η) 200mg sample is phenol / tetrachloroethane = 50/50
After heating for 30 minutes at about 110 ° C, add
Was measured.

(6) Heat shrinkage (%) of the film The film is heat shrunk for 3 minutes with no load during the guard open at a temperature of 150 ± 2 ° C, and the heat shrinkage in the vertical and horizontal directions is calculated according to the following formula. Was.

However, ₀ : original length 10 cm: length after shrinkage (7) Evaluation of formability A laminate with a steel sheet was prepared, drawn according to a conventional method, and formability was evaluated based on the following criteria.

Good without peeling etc. ○ Partially peeled or partially cracked △ Fully peeled or cracked × Example 1 77 mol% of terephthalic acid unit as dicarboxylic acid component,
It is composed of 18 mol% of isophthalic acid units and 5 mol% of sebacic acid units, and 90 g of ethylene glycol units as a diol component.
pre-crystallized copolymer polyester containing 500 ppm of amorphous silica fine particles having an average particle size of 1.4 μm consisting of 2 mol% of diethylene glycol units and 2 mol%, and then dried, extruded at 280 ° C. using an extruder having a T-die, and quenched. It was solidified to obtain an amorphous sheet. The obtained sheet was stretched 3.0 times in the longitudinal direction at 75 ° C. between the heating roll and the cooling roll, and subsequently stretched 3.6 times in the transverse direction at 95 ° C., and the transverse relaxation of 15% and 0.5%
The heat treatment was performed at 170 ° C. while relaxing in the vertical direction. The average thickness of the obtained film was 38 μm, and the intrinsic viscosity was 0.66.

The obtained film was laminated on a steel plate and its formability was evaluated.

Comparative Example 1 82 mol% of terephthalic acid units as a dicarboxylic acid component
A copolymer polyester containing 18 mol% of isophthalic acid units and ethylene glycol as a diol component and containing particles similar to that of Example 1 was used.
Drying and film formation were carried out in exactly the same manner as in Example 1 except that the temperature was changed to ° C. to obtain a film (intrinsic viscosity: 0.65) having an average thickness of 38 μm. The obtained film was laminated with a steel plate, and the formability was evaluated.

Comparative Example 2 The moldability of the obtained molded article was evaluated in exactly the same manner as in Example 1 except that the longitudinal stretching ratio was 3.5 times.

Comparative Example 3 When the heat treatment temperature was set to 200 ° C. in Example 1,
The film melted and broke.

When the degree of plane orientation was measured for the fractured sample
It was 0.035. On the other hand, the strength at 100% elongation
The film could not be stretched to 0% and could not be measured.

Example 2 80 mol% of terephthalic acid units as a dicarboxylic acid component
100 ppm of amorphous silica particles having an average particle size of 1.0 μm, comprising 15 mol% of isophthalic acid units and 5 mol% of sebacic acid units, and ethylene glycol units as a diol component.
Pre-crystallize the copolyester containing
The mixture was extruded from an extruder having a T-die at ℃ and quenched and solidified to obtain an amorphous sheet having an intrinsic viscosity of 0.66. After stretching the obtained sheet 3.3 times in the longitudinal direction at 85 ° C., then in the transverse direction at 100 ° C.
The film was stretched 3.5 times, and heat-treated at 185 ° C. while performing 10% relaxation in the width direction and 0.5% relaxation in the longitudinal direction. The average thickness of the obtained film was 38 μm. The obtained film was laminated with a steel plate, and its formability was evaluated.

Example 3 Copolyester comprising 94 mol% of terephthalic acid units and 6 mol% of adipic acid units as dicarboxylic acid components, 70 mol% of ethylene glycol units and 30 mol% of 1,4-cyclohexane dimethanol units as diol components, and average particle size Polyethylene terephthalate containing 2,000 ppm of kaolin (1.1 μm) was mixed at a ratio of 70/30 (wt%), and then dried, extruded and formed into a film exactly as in Example 2 to obtain a film having an average thickness of 38 μm. The intrinsic viscosity of the film was 0.68. The obtained film was laminated with a steel plate, and its formability was evaluated.

Comparative Example 4 The test was carried out using a copolymer polyester containing 97 ppm of terephthalic acid units and 3 mol% of isophthalic acid units as dicarboxylic acid components and 100 ppm of amorphous silica particles having an average particle size of 1.0 μm and consisting of ethylene glycol as a diol component. Drying and extrusion were carried out in the same manner as in Example 1 to obtain an amorphous sheet having an intrinsic viscosity of 0.62. The obtained amorphous sheet was stretched and heat-treated at 200 ° C. under tension and fixing in the same manner as in Example 2 to obtain a film having an average thickness of 38 μm. The obtained film was laminated with a steel plate, and its formability was evaluated.

Comparative Example 5 83 mol% of terephthalic acid units as a dicarboxylic acid component
Consists of 14 mol% of isophthalic acid units and 3 mol% of sebacic acid units, and 98 mol of ethylene glycol units as a diol component
A copolymerized polyester (A) comprising l% and 2 mol% of diethylene glycol units and containing 500 ppm of amorphous silica fine particles having an average particle size of 1.4 μm was polymerized by a conventional method. The obtained copolyester (A) was crystallized, dried, extruded at 270 ° C., and quenched and solidified to obtain an amorphous sheet.

The obtained sheet was stretched 3.5 times at 77 ° C. in the longitudinal direction between a heating roll and a cooling roll, and subsequently stretched at 95 ° C. in the transverse direction.
The sheet was stretched 3.6 times, and heat-treated at 185 ° C. while performing 15% relaxation in the horizontal direction and 0.5% relaxation in the vertical direction. The average thickness of the obtained film was 38 μm, and the intrinsic viscosity was 0.65. The obtained film was laminated with a steel plate, and its formability was evaluated.

 The results obtained above are shown in Table 1 below.

(Effect of the Invention) The molded article of the present invention exhibits excellent moldability, can be applied to various uses by drawing, and has high industrial value.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B32B 15/08

Claims (1)

(57) [Claims] (1) The strength at 100% elongation F _{100 in an} atmosphere of 150 ° C.
A molded product obtained by laminating a steel plate on a biaxially oriented polyester film having a thickness of 5 to 5.0 kg / mm ² , a degree of plane orientation ΔP in a range of 0.050 to 0.110, and a thickness unevenness of 40% or less.