JP2006305929A - Manufacturing method of stretched thermoplastic polyester-based resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stretched thermoplastic polyester-based resin sheet excellent in tensile strength, elastic modulus in tension and heat resistance. <P>SOLUTION: In order to manufacture this stretched thermoplastic polyester-based resin sheet, an amorphous thermoplastic polyester-based resin sheet is heated up to a temperature higher than the glass transition temperature of the thermoplastic polyester-based resin and then drawn and stretched by drawing between a pair of rolls heated up to a temperature, which is below the glass transition temperature of the thermoplastic polyester-based resin and not lower than the glass transition temperature minus 20°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a stretched thermoplastic polyester resin sheet, and more particularly to a method for producing a stretched thermoplastic polyester resin sheet having excellent tensile strength, tensile elastic modulus, and heat resistance.

Conventionally, a method for producing a transparent crystalline polymer sheet having a smooth surface and a high strength and elastic modulus by pultrusion has been studied. For example, crystals of polyethylene, polypropylene, polyacetal resin, nylon, etc. The temperature of the base sheet of the differential polymer calorimetric melting curve is not exceeded the deformation start temperature when the sheet is heated at a rate of temperature increase of 1 ° C./min with a 10 MPa load applied to the sheet. There has been proposed a method for producing a crystalline polymer sheet, which is drawn through at least a drawing ratio of 2.5 times or more through a pair of heated rollers (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 60-15120

Further, in the pultrusion molding, a method for producing a crystalline polymer sheet has been proposed in which the strength of the sheet after stretching is increased by quenching immediately after drawing, and the stretching speed can be increased by increasing the drawing temperature. (For example, refer to Patent Document 2).
Japanese Patent Publication No. 06-4273

However, in the above method for producing a crystalline polymer sheet, when a polyester resin is stretched, the molecular orientation is relaxed when the drawing temperature is raised, and the strength is not increased even when stretched at a high magnification, which is not desirable.
On the other hand, the flexibility required for stretching cannot be obtained at low temperatures, and voids are generated and the strength is lowered. Therefore, a stretched sheet having high strength cannot be obtained by stretching. For this reason, it is necessary to perform pultrusion molding in the temperature range of the glass transition temperature of the polyester resin −20 ° C. to the glass transition temperature + 20 ° C., and more preferably, stretching near the glass transition temperature.

  In addition, the method of providing the quenching region not only complicates the equipment, but also when stretching the polyester resin, it is not preferable to raise the temperature of the drawing roller because orientation relaxation occurs immediately after stretching.

  An object of the present invention is to provide a method for producing a stretched thermoplastic polyester resin sheet excellent in tensile strength, tensile elastic modulus, and heat resistance in view of the above-mentioned drawbacks.

  In the method for producing a stretched thermoplastic polyester resin sheet according to claim 1 of the present invention, the amorphous thermoplastic polyester resin sheet is heated to a temperature equal to or higher than the glass transition temperature of the thermoplastic polyester resin. The thermoplastic polyester resin is drawn and drawn through a pair of rolls having a temperature lower than the glass transition temperature and a glass transition temperature of −20 ° C. or higher.

  The stretched thermoplastic polyester resin sheet according to claim 2, wherein the stretched thermoplastic polyester resin sheet according to claim 2 is drawn and stretched and then uniaxially stretched at a temperature higher than the temperature of the roll. A stretched thermoplastic polyester resin sheet having excellent tensile strength, tensile elastic modulus, and heat resistance can be obtained.

  The method for producing a stretched thermoplastic polyester resin sheet according to claim 3, wherein the uniaxial stretching temperature is the rising temperature of the crystallization peak of the thermoplastic polyester resin in the differential operation calorimetric curve measured at a heating rate of 1 ° C / min. It is the rising temperature of the melting peak. The method for producing a stretched thermoplastic polyester resin sheet according to claim 2, wherein the stretched thermoplastic polyester resin sheet can be suitably uniaxially stretched.

  4. The method for producing a stretched thermoplastic polyester resin sheet according to claim 4, wherein the uniaxially stretched stretched polyester resin sheet is heat-set at a temperature higher than the uniaxial stretch temperature. And a stretched thermoplastic polyester resin sheet excellent in tensile strength, tensile elastic modulus and heat resistance is obtained.

  6. The method for producing a stretched thermoplastic polyester resin sheet according to claim 5, wherein the heat setting temperature is a melting peak of the thermoplastic polyester resin in a differential operation calorimetric curve measured at a uniaxial stretching temperature to a heating rate of 1 ° C./min. 5. The method for producing a stretched thermoplastic polyester resin sheet according to claim 4, wherein the heat setting can be stably and reliably performed.

  The method for producing a stretched thermoplastic polyester resin sheet according to claim 6 is characterized in that the heat setting is performed in a state where the stretched thermoplastic polyester resin sheet that has been uniaxially stretched is fixed so as not to shrink due to heat. Item 6. The method for producing a stretched thermoplastic polyester resin sheet according to Item 4 or 5, wherein the heat setting can be performed more stably and reliably.

  Examples of the thermoplastic polyester resin used in the present invention include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyglycolic acid, poly (L-lactic acid), poly (3-hydroxybutyrate), poly ( 3-hydroxybutyrate / hydroxyvalerate), poly (ε-caprolactone), polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene succinate / lactic acid, polybutylene succinate / carbonate, polybutylene succinate Nate / terephthalate, polybutylene adipate / terephthalate, polytetramethylenadipate / terephthalate, polybutylene succinate / adipate / terephthalate, etc. Polyethylene terephthalate is preferable.

  Although the thickness of a thermoplastic polyester-type resin sheet is not specifically limited, 0.5-4 mm is preferable. If it is less than 0.5 mm, the thickness of the sheet after stretching becomes too thin, and the strength during handling may not be sufficient, and if it exceeds 4 mm, stretching may be difficult.

  In the present invention, the thermoplastic polyester resin sheet in the amorphous state is drawn through a pair of rolls and drawn and stretched.

  The temperature of the thermoplastic polyester resin sheet when drawing and drawing is low, the drawn thermoplastic polyester resin sheet is whitened or too hard to be drawn, and when it becomes high, the strength decreases due to orientation relaxation. Therefore, it is heated in advance to the glass transition temperature or higher of the thermoplastic polyester resin before drawing and stretching, and is preferably glass transition temperature + 20 ° C. or lower.

In the present invention, a thermoplastic polyester resin sheet heated in advance is supplied to a pair of rolls, drawn between the rolls and stretched.
By lowering the roll temperature below the preheating temperature, the film is cooled at the same time as it is stretched, preventing the resin temperature from rising due to frictional heat during drawing, etc. To do.

  When the temperature of the pair of rolls during drawing and drawing is low, the flexibility necessary for drawing cannot be obtained, and voids are generated in the sheet at the time of drawing and the strength is lowered. Since it is not possible to obtain a high-strength sheet by relaxation, the glass transition temperature of the thermoplastic polyester resin is lower than the glass transition temperature of the thermoplastic polyester resin, that is, not more than the temperature of the thermoplastic polyester resin sheet. A temperature range of −20 ° C. or higher, preferably a temperature range of less than the glass transition temperature of the thermoplastic polyester resin and a glass transition temperature of −10 ° C. or higher of the thermoplastic polyester resin.

  Further, when the amorphous polyester resin sheet in the amorphous state is pulled out, the pair of rolls does not need to rotate, but may be slightly rotated in the pulling direction in order to make the temperature distribution uniform.

  The draw ratio of the above-described drawing stretching is not particularly limited. However, if the stretching ratio is low, a sheet excellent in tensile strength and tensile elastic modulus cannot be obtained. If the stretching ratio is high, the sheet tends to break during stretching. 2-9 times is preferable, More preferably, it is 4-8 times.

  The stretched thermoplastic polyester resin sheet drawn and stretched in the present invention may be uniaxially stretched at a temperature higher than the temperature of the roll in order to improve physical properties such as tensile strength, tensile elastic modulus, and heat resistance.

  The polyester resin of the drawn stretched thermoplastic polyester resin sheet that has been drawn and stretched has high strength because the molecular chains are highly oriented in a state where isotropic crystallization and orientation are suppressed by heat, which is an impediment to stretching. Although the elastic modulus is excellent, the degree of crystallinity is low. Therefore, when heated, the orientation is easily relaxed and the elastic modulus is lowered.

  However, the stretched thermoplastic polyester resin sheet that has been drawn and stretched is uniaxially stretched at a temperature higher than that of the roll, so that the degree of crystallinity is increased without relaxation and the orientation is easy even when heated. Thus, a stretched sheet having excellent heat resistance that is not relaxed can be obtained.

  As the uniaxial stretching method, a roll stretching method is preferably used. The roll stretching method is a method in which a stretched raw fabric is sandwiched between two pairs of rolls having different speeds, and the stretched raw fabric is pulled while being heated, and the molecular orientation can be strongly oriented only in a uniaxial direction. In this case, the speed ratio of the two pairs of rolls becomes the draw ratio.

  The temperature at the time of uniaxial stretching may be higher than the temperature of the pair of rolls at the time of drawing and drawing, but if it is too high, the drawn and stretched thermoplastic polyester resin sheet is melted and cut. The temperature range from the rising temperature of the crystallization peak of the thermoplastic polyester resin to the rising temperature of the melting peak in the differential operation calorie curve measured at a heating rate of 1 ° C./min is preferable.

  The rising temperature of the crystallization peak of polyethylene terephthalate is about 120 ° C., and the rising temperature of the melting peak is about 230 ° C. Accordingly, when the polyethylene terephthalate sheet is uniaxially stretched, it is preferably uniaxially stretched at about 120 to about 230 ° C.

  The stretching ratio of the uniaxial stretching is not particularly limited, but if the stretching ratio is low, a sheet excellent in tensile strength and tensile elastic modulus cannot be obtained. If the stretching ratio is high, the sheet tends to break during stretching. 1.1-3 times are preferable, More preferably, it is 1.2-2 times. Moreover, the total draw ratio of primary stretching and uniaxial stretching is preferably 2.5 to 10 times for the same reason.

  Furthermore, it is preferable to heat-set in order to improve the heat resistance of the uniaxially stretched stretched polyester resin sheet.

  If the heat setting temperature is lower than the uniaxial stretching temperature, the crystallization of the thermoplastic polyester resin does not proceed, so the heat resistance is not improved, and the thermoplastic polyester system in the differential operation calorimetric curve measured at a heating rate of 1 ° C./min. If the temperature rises above the rise temperature of the melting peak of the resin, the thermoplastic polyester-based resin dissolves and the stretching (orientation) disappears, and the tensile modulus, tensile strength, etc. decrease, so the uniaxial stretching temperature to the heating rate of 1 ° C./min. The rising temperature of the melting peak of the thermoplastic polyester resin in the measured differential operation calorimetric curve is preferred.

  In addition, when heat-fixed, the stretched thermoplastic polyester resin sheet is stretched if a load is applied, and contracts in a free state. Therefore, the stretched thermoplastic polyester resin sheet is not loaded but is shrunk by heat. It is preferable to carry out in the state fixed so that it may not carry out, and it is preferable that the stretched thermoplastic polyester-type resin sheet is not pressurized. For example, it is preferable to heat-set in a state where both ends of the stretched thermoplastic polyester resin sheet are held so as not to be loaded with a pinch roll or the like. Therefore, heating is preferably performed with hot air, a heater, or the like.

  The time for heat setting is not particularly limited, and is generally 10 seconds to 5 minutes, although it varies depending on the thickness of the stretched thermoplastic polyester resin sheet and the heat setting temperature.

  The stretched thermoplastic polyester resin sheet produced by the method for producing a stretched thermoplastic polyester resin sheet of the present invention is excellent in tensile strength, tensile elastic modulus, and heat resistance. It is preferably used.

  The stretched thermoplastic polyester resin sheet may be used by being laminated, or other unstretched thermoplastic polyester resin sheet, stretched polyolefin resin sheet, polyolefin resin, vinyl chloride resin, You may laminate | stack with thermoplastic resin sheets, such as ABS resin, AES resin, AS resin, and acrylate resin.

  The structure of the manufacturing method of the extending | stretching thermoplastic polyester-type resin sheet of this invention is as the above-mentioned, and the extending | stretching thermoplastic polyester-type resin sheet obtained is excellent in tensile strength, a tensile elasticity modulus, and heat resistance. In particular, a stretched thermoplastic polyester resin sheet that has been uniaxially stretched is more excellent in heat resistance, and a stretched thermoplastic polyester resin sheet that has been heat-fixed after uniaxial stretching is further superior in heat resistance.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

Example 1
A polyethylene terephthalate sheet (made by Teijin Chemicals, trade name “A-PET sheet FR”) having a thickness of 1 mm and a width of 200 mm is supplied to a stretching apparatus (manufactured by Kyowa Engineering Co., Ltd.), preheated to 75 ° C., and then heated to 63 ° C. A drawn polyethylene terephthalate sheet having a draw ratio of about 5 was obtained by drawing and drawing between the pair of rolls (roll interval 0.2 mm) at a speed of 2 m / min.

  The polyethylene terephthalate sheet has a glass transition temperature of 72 ° C., a rising temperature of a crystallization peak in a differential operating calorimetry curve measured at a heating rate of 1 ° C./min, about 118 ° C., and a rising temperature of a melting peak is about It was 230 ° C.

(Example 2)
A polyethylene terephthalate sheet (made by Teijin Kasei Co., Ltd., trade name “A-PET sheet FR”) having a thickness of 1 mm and a width of 200 mm is supplied to a stretching apparatus (manufactured by Kyowa Engineering Co., Ltd.), preheated to 75 ° C., and then heated to 66 ° C. A drawn polyethylene terephthalate sheet having a draw ratio of about 5 was obtained by drawing and drawing between the pair of rolls (roll interval 0.2 mm) at a speed of 2 m / min.

(Comparative Example 1)
A polyethylene terephthalate sheet (made by Teijin Chemicals, trade name “A-PET sheet FR”) having a thickness of 1 mm and a width of 200 mm is supplied to a stretching apparatus (manufactured by Kyowa Engineering Co., Ltd.), preheated to 75 ° C., and then heated to 74 ° C. A drawn polyethylene terephthalate sheet having a draw ratio of about 5 was obtained by drawing and drawing between the pair of rolls (roll interval 0.2 mm) at a speed of 2 m / min.

(Comparative Example 2)
A polyethylene terephthalate sheet (made by Teijin Chemicals, trade name “A-PET sheet FR”) having a thickness of 1 mm and a width of 200 mm is supplied to a stretching apparatus (manufactured by Kyowa Engineering Co., Ltd.), preheated to 75 ° C., and then heated to 78 ° C. A drawn polyethylene terephthalate sheet having a draw ratio of about 5 was obtained by drawing and drawing between the pair of rolls (roll interval 0.2 mm) at a speed of 2 m / min.

  The stretched elastic modulus and tensile strength in the stretching direction of the obtained stretched polyethylene terephthalate sheet were measured according to the tensile test method of JIS K 7113, and the results are shown in Table 1.

Claims (6)

  After heating the amorphous polyester resin sheet in an amorphous state to a temperature equal to or higher than the glass transition temperature of the thermoplastic polyester resin, the glass transition temperature is lower than the glass transition temperature of the thermoplastic polyester resin and the glass transition temperature is −20 ° C. or higher. A method for producing a stretched thermoplastic polyester-based resin sheet, wherein the stretched thermoplastic polyester resin sheet is drawn and drawn through a pair of rolls at a temperature.   2. The method for producing a stretched thermoplastic polyester resin sheet according to claim 1, wherein the stretched thermoplastic polyester resin sheet is stretched uniaxially at a temperature higher than the temperature of the roll after the drawing.   The uniaxial stretching temperature is a rising temperature of a crystallization peak of a thermoplastic polyester resin to a rising temperature of a melting peak in a differential operation calorie curve measured at a heating rate of 1 ° C / min. Method for producing a stretched thermoplastic polyester resin sheet.   4. The method for producing a stretched thermoplastic polyester resin sheet according to claim 2, wherein the stretched thermoplastic polyester resin sheet that has been uniaxially stretched is heat-set at a temperature higher than the uniaxial stretching temperature.   The heat of stretching according to claim 4, wherein the heat setting temperature is a rising temperature of a melting peak of the thermoplastic polyester resin in a differential operation calorie curve measured at a uniaxial stretching temperature to a heating rate of 1 ° C / min. A method for producing a plastic polyester resin sheet.   The method for producing a stretched thermoplastic polyester resin sheet according to claim 4 or 5, wherein the heat setting is performed in a state where the stretched thermoplastic polyester resin sheet that has been uniaxially stretched is fixed so as not to shrink by heat.