JPS6153394B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermal adhesive composite material in which a polyether ester copolymer and a long fiber nonwoven fabric are integrated, and in particular, the thermal adhesive has excellent shape retention at high temperatures, flexibility at low temperatures, crack resistance, and bending resistance. This study concerns composite materials. BACKGROUND ART Conventionally, polyvinyl chloride, polyethylene, polypropylene, etc., have been used as exterior coverings for electric wires and cables, flexible metal pipes, and various coated steel pipes by melt extrusion coating. Articles made using these conventional melt extrusion methods have poor performance such as flexibility at low temperatures, heat resistance, crack resistance, and bending resistance, which not only limits the usage conditions, but also makes it difficult to use during the coating process. Because the method coats short lengths by melt extrusion, there is a lot of loss at the joints, and when coating large-diameter steel pipes, the steel pipes themselves have to be rotated, which increases the size of the equipment. The object of the present invention is to eliminate these drawbacks of the prior art and provide a heat-adhesive composite material with excellent coating workability and gloss on the surface of the coating. That is, the present invention comprises a polyether ester copolymer composed of a polyether segment and a polyester segment and having a melting point of 110 to 180°C, and a polyether ester copolymer having a fineness of 1 to 180°C.
This is a heat-adhesive composite material characterized by being integrated with a long fiber nonwoven fabric made of 10 denier long fibers and having a basis weight of 20 to 300 g/m ² . The polyetherester copolymer used in the present invention consists of polyester segments and polyether segments, and has a melting point of 110 to 180°C, preferably
The temperature is 120-170°C, particularly preferably 145-170°C.
The polyester segment is composed of a dicarboxylic acid component and a diol component, but in the present invention, the dicarboxylic acid is substantially limited to terephthalic acid and isophthalic acid, and the diol is limited to 1,4-butanediol. Therefore, it can be said that the polyester segment of the present invention is essentially polybutylene terephthalate isophthalate (hereinafter abbreviated as PBT/I) or polybutylene terephthalate (abbreviated as PBT). Of course, in addition to these, dicarboxylic acids such as phthalic acid, adipic acid, and sebacic acid, or diols such as ethylene glycol, diethylene glycol, and neopentyl glycol can be used in combination within a range that does not impair the purpose. On the other hand, the polyether segment is essentially polytetramethylene glycol (abbreviated as PTMG)
However, small amounts of polyethylene glycol, polypropylene glycol, etc. can also be used in combination as long as the purpose is not impaired. The molecular weight of PTMG is usually
400 to 10,000 is generally used, preferably 700 to 2,500, particularly preferably 800 to 1,500. Thus, the polyether ester copolymer used in the present invention is essentially polybutylene terephthalate isophthalate polytetramethylene glycol (abbreviated as Polymer A or PBT/I-PTMG) consisting of PBT/I and PTMG; Alternatively, it is polybutylene terephthalate polytetramethylene glycol (abbreviated as Polymer B or PBT-PTMG) consisting of PBT and PTMG. And the overall melting point of polymer A and polymer B is
It is essential that the temperature be within the range of 110 to 180°C. The melting point of the entire polymer is a factor that has a significant effect on the thermal adhesiveness and surface gloss of the composite material of the present invention, and unless it is within this range, sufficient thermal adhesiveness and a glossy surface cannot be obtained. If the melting point is less than 110°C, the composite material becomes sticky and blocks, resulting in poor workability such as unwinding and transporting the composite material into a roll, and lacks heat resistance. On the other hand, if the temperature exceeds 180℃, the thermal adhesion will be insufficient, so when tape-shaped composite materials are taped to the base material of cables or pipes and thermally bonded to each other or to the base material, the thermal bonding may be insufficient. There are disadvantages such as fading and lack of gloss on the coated surface. For applications where long-term shape retention at high temperatures is important, those with a melting point of 145°C to 170°C are particularly preferred. In applications such as coating metal substrates, it is preferable to use Polymer A when not only thermal adhesion between composite materials but also thermal adhesion with the metal substrate is required. In particular, when a high polymer is formed only from the polyester segment components of Polymer A, the melting point is 120°C to 200°C, preferably 130 to 190°C.
It is preferable to use a polymer having a PTMG content of 15 to 70 wt%, preferably 20 to 60 wt%, based on the entire polymer A. If the melting point of the polyester segment of Polymer A is less than 120°C, there will be problems with blocking of the composite material and heat resistance.
If the temperature exceeds ℃, metal adhesion is lost. Depending on the purpose, necessary amounts of antioxidants, heat stabilizers, weathering agents, pigments, dyes, inorganic fine particles, organic lubricants, etc. can be added to the polyether ester copolymer. In addition, polyethylene, ethylene/vinyl acetate copolymers, maleic anhydride, and other α- and β-
Polyolefins, ionomers, and ionomers modified by graft polymerization of ethylenically unsaturated acids and their derivatives.
A polymer such as a polyester copolymer may be mixed in an amount of 30 wt% or less, preferably 25 wt% or less, based on the polyether ester copolymer. The melting point of the polyether ester copolymer was measured by the penetration method under the following conditions, and it almost coincides with the melting point measured by a differential calorimeter. That is, a sample that had been heat-treated in advance at 80℃ for about 15 hours in a nitrogen stream was set in a penetrometer, a 5g load was applied to a pin with a diameter of 0.5mm, and the temperature was raised at a rate of 10℃/min in a nitrogen stream. , the pin
The melting point was defined as the temperature at which the material penetrated 250μ. The melting point of a polyester segment is determined by making a polymer containing only the corresponding polyester component, heat-treating it at a temperature approximately 20°C lower than the expected melting point, and then measuring the melting point in the same manner as for polyether ester. It was considered as the melting point. On the other hand, the long fibers referred to in the present invention have a fiber length of 80 mm or more, preferably 100 mm or more, and a fineness of 1 to 10 deniers, preferably 2 to 8 deniers. The fabric weight of the long fiber nonwoven fabric used in the present invention is 20~
300g/ ^m2 , preferably 30-100g/ ^m2 . Such long fiber nonwoven fabrics can be made by a spunbond method. As a method for joining long fiber webs, ordinary adhesive joining and mechanical joining are applied. As the adhesive, from the viewpoint of heat resistance and crack resistance of the composite material, a resin having a melting point higher than that of the polyether ester copolymer and lower than the melting point of the fibers constituting the nonwoven fabric is preferable. By mixing such resin in the form of fibers or powder into a nonwoven fabric and heat-sealing the resin, each fiber of the nonwoven fabric can be bonded and fixed. The fiber material constituting the nonwoven fabric is one that is adhesive to the polyether ester copolymer and has a higher melting point than these, preferably one with a higher melting point of 200° C. or higher. Preferred examples of such fiber materials include polyethylene terephthalate, nylon 6, and copolymers thereof. In particular, nonwoven fabrics of polyethylene terephthalate and its copolymers are preferred in terms of heat resistance and crack resistance when made into composite materials. The fineness of the fibers that make up the nonwoven fabric is 1 to 10.
If the fineness is less than 1 denier, the composite material will not have any reinforcing effect, and if it exceeds 10 denier, the surface of the composite material will have large irregularities when thermally bonded and will not be glossy. Further, the basis weight of the long fiber nonwoven fabric must be maintained at 20 to 300 g/m ² . This is because if the basis weight is less than 20 g/m ² , the composite material will not have a reinforcing effect, and if it exceeds 300 g/m ² , it will not be possible to make a thin composite material, resulting in poor flexibility. On the other hand, when a nonwoven fabric with short fibers having a fiber length of less than 80 mm is used, the composite material has drawbacks such as insufficient crack resistance and poor shape retention at high temperatures. Furthermore, when a woven fabric is used instead of a non-woven fabric, it is strong in the warp and weft directions of the woven fabric, but weak in other directions.
When a metal tube or the like is wound in a helical shape and heat-sealed, there is a drawback that the fibers at the end of the tape curl up, spoiling the appearance. Depending on the purpose, antioxidants, heat stabilizers, weathering agents, pigments, dyes, inorganic fine particles, and the like can be added in necessary amounts to the fiber material constituting the long fiber nonwoven fabric used in the present invention. The composite material of the present invention is made by integrating the above-mentioned polyether ester copolymer and long-fiber nonwoven fabric, but the methods for integrating these are as follows: A method of compounding with a copolymer. In this case, by adjusting the press pressure,
The nonwoven fabric can be partially or completely embedded in the polyetherester copolymer. (2) There is a method in which a film of polyether ester copolymer is formed in advance, and the film is laminated with a nonwoven fabric and composited using a hot press. The thickness of the composite material of the present invention can be changed widely by changing the basis weight and thickness of the nonwoven fabric used and the thickness of the polyether ester copolymer, so it can be selected as appropriate depending on the application.
For normal applications, 0.1 to 2 mm is used. The composite material of the present invention is used in the form of a sheet or tape depending on its intended use. Typical examples of applications include the following. (1) Used in tape form as a covering layer for electric wires and cables. (2) Used in tape form on the exterior of flexible metal pipes. (3) Used in tape form on the exterior of plastic-coated metal pipes (especially pre-bent metal pipes). When the composite material of the present invention is used in the form of a tape for the above-mentioned applications, it has the following advantages in the coating process, which greatly simplifies the process. In other words, when coating products that are made while rotating, such as twisted electric wires or flexible pipes made of spirally wound metal strips, it is difficult to directly coat the products using the melt extrusion method. The material was once cut to a certain length and then melt-extruded and coated in a separate process. However, if the composite material of the present invention is used in the form of a tape, it can be taped using the product's rotation and then thermally bonded in a heating furnace to cover the product all at once, so there is no need to separate the process. This has the advantage of being able to produce long products without any problems, and with less loss. The composite material of the present invention has good adhesion to other composite materials, metals such as iron and aluminum, glass, polyester, polyvinyl chloride, plastics such as nylon 6, etc.
Used for the exterior of flexible metal pipes and other general metal pipes. The composite material of the present invention can be bonded by conventional thermal bonding methods. Examples include a hot plate heat sealer, a heat press, a method of heating and fusing the surface with hot air or an infrared heater, an ultrasonic sealing method, and an induction heating method. Since the composite material of the present invention is a heat-adhesive composite material in which a long fiber nonwoven fabric and a polyether ester copolymer are integrated, it has the following excellent effects. (1) Good form support (heat resistance) at high temperatures. (2) Good flexibility at low temperatures. (3) Excellent crack resistance and bending resistance. (4) Excellent adhesion resistance and coated articles have good gloss. (5) It is easy to handle because it does not block and has a regular waist. (6) Taping workability is good, and tapes can be easily joined together by thermal adhesion, reducing product loss. (7) Taping can be done during the process of rotating the product, which simplifies the coating process. (8) The melt extrusion coating device can be replaced with a simple device for taping and heat fusion, simplifying the process and improving yield. The present invention will be specifically described below with reference to Examples, in which physical properties were measured in the following manner. (1) Blocking Judgment was made based on the blocking state when the composite material was wound into a roll or unwound from a roll. 〇: Smooth winding and unwinding without blocking. Δ: Slight blocking is observed. ×: Severe blocking, wrinkles appearing during winding, or failure to unwind normally. (2) Taping suitability Judgment was made based on the following criteria based on workability when taping tape-shaped composite materials. 〇: No particular troubles occurred during taping,
The tape will not shift during handling until it is thermally bonded. △: The tape becomes thinner in the width direction due to elongation, and the tape tends to shift slightly during handling. ×: The tape breaks or the tape shifts and unravels during handling. (3) Thermal adhesiveness After taping a tape-shaped composite material onto a rod-shaped or pipe-shaped article and thermally adhering it to form a covering layer, the covering layer was cut open and the state of thermal adhesion between the tapes was observed. ○: The tapes are well adhered to each other and are integrated. △: Adhesion is slightly weak, but not a problem in practical use. ×: Adhesion is incomplete and the tapes can be easily peeled off. (4) Cold resistance The heat-bonded coated article was cooled to -40°C, bent to a curvature within the shape recovery range of the article, and the presence or absence of cracks in the coating layer was examined. ○: No cracks. ×: There are cracks. (5) Heat resistance After the heat-bonded coated parts were left in an oven at 140°C for 400 hours, judgment was made from the flow of resin on the surface of the coating layer and the appearance of cracks in the coating layer when bent. ○: No abnormalities such as resin flow or cracks are observed. ×: Resin flows and drips or cracks occur. (6) Crack resistance A cut was made in the coating layer of the thermally bonded coated article with a razor blade, and the cut was bent 10 times and the spread of the cut was observed. ○: The cut does not widen. △: The cut area is slightly widened. ×: The cut area widens widely without resistance. Example 1 (1) Preparation of long fiber nonwoven fabric Polyethylene terephthalate (abbreviated as PET) [intrinsic viscosity measured in orthochlorophenol at 25°C, IV = 0.70] and polyethylene terephthalate adipate (PET/A) as a low melting point polymer were used. PET:PET/A=
The fibers were discharged at a ratio of 10:1, and the fibers were stretched by an air stream and deposited in a web on a moving belt. This web was passed through a thermal calendar roll to intermittently thermally bond the filament yarns together to produce nonwoven fabrics of various basis weights. The single yarn fineness of this nonwoven fabric is 5 denier, and the basis weight is 30, 50, and 80, respectively.
g/ ^m2 . (2) Preparation of polyether ester copolymer PBT/I-PTMG (75/25-40) (The polyester segment is polybutylene terephthalate/isophthalate with a molar ratio of terephthalic acid and isophthalic acid of 75/25. A polymer (No. A-1) was polymerized, indicating that the proportion of the ether segment in the total copolymer was 40% by weight. The physical properties of this polymer are: intrinsic viscosity IV = 1.80 measured in orthochlorophenol at 25°C;
Melting point 165℃, polyester segment melting point 182
℃, and PTMG molecular weight was 1000. To this was added 1.5 wt% of the amine additive "Naugard" 445 (manufactured by Uniroyal) as a heat resistant agent. (3) Preparation of composite material Polymer No. A-1 was supplied to an extrusion laminator with a diameter of 40 mm, melted and extruded at 260°C, and during the solidification process, it was integrated with the long fiber nonwoven fabric using a press roll. Various composite materials shown in Table 1 were made. The thickness was approximately 170 μm, and the nonwoven fabric was almost completely buried in the fabric to the extent that some of the threads of the nonwoven fabric were visible on one side.

[Table] Composite materials Nos. 1 to 3 of the present invention had no blocking and were easy to handle. These composite materials were slit to a width of 6 mm to make a tape, taped with a 1/2 wrap to a flexible steel pipe with a diameter of 7 mm, and then heated with an infrared heater at 200°C for 2 minutes.
The tape was fused to make a coated steel pipe. As shown in the evaluation results in Table 1, the coated steel pipe was suitable for taping, had good thermal adhesion, and had good gloss. It was found that this composite material has excellent cold resistance, heat resistance, and crack resistance, making it an excellent composite material for the exterior of flexible metal pipes. For comparison, we similarly evaluated a 170μ film (No. 4) made only of Polymer A without using nonwoven fabric, and found that there was a large amount of blocking, the film stretched when taped, causing it to become thin and cut, and the coating was poor. It was incomplete and had poor thermal adhesion and cold resistance. In addition, if it is left at 140℃ for a long period of time, Polymer A
The material sagged under its own weight, had no form support at high temperatures, and had significantly poor crack resistance. Also, instead of non-woven fabric, PET tricot fabric (15 denier, basis weight)
No. 5 using 48 g/m ² ) had a serious drawback that the fibers fluffed from the edge of the tape during thermal bonding, resulting in incomplete coverage. Thus, it has been found that the use of long fiber nonwoven fabric is optimal for the composite material of the present invention. Example 2 (1) Long fiber nonwoven fabric Used in Example 1, fineness 5 denier, basis weight 80
g/m ² nonwoven fabric was used. For comparison, a long fiber nonwoven fabric with a fineness of 15 denier and a basis weight of 100 g/m ² was prepared in the same manner as in Example 1. (2) Polyetherester PBT/I-PTMG (70/30-50) polymer
No.A-2 (IV=1.70, melting point 155℃, melting point of polyester segment 175℃, molecular weight of PTMG
1000), PBT/1-PTMG (65/35-30) Polymer No. A-3 (lV = 1.85, melting point 150°C, melting point of polyester segment 160°C, molecular weight of PTMG 1000), PBT/1-PTMG (65/35-30) for comparison. I-PTMG
(90/10-10) Polymer No.A-4 (IV=1.93,
Melting point 200℃, polyester segment melting point 208
℃, prepared PTMG with a molecular weight of 1000, and added the hindered phenol heat resistant agent “Irganox” to each polymer.
1010 (manufactured by Ciba Geigy) 0.3 wt% was added. (3) Composite material Using the apparatus of Example 1, a composite material was made from the combinations of nonwoven fabric and polymer A shown in Table 2.

[Table] In Nos. 6 and 7 of the present invention, the nonwoven fabric was almost completely embedded in the polymer A to the extent that some nonwoven fabric fibers were seen on one side, and the blocking was good (○).
After forming the composite material into a tape with a width of 12 mm, the diameter is 13 mm.
A coated metal pipe was made by taping a flexible steel pipe with 1/2 wrap and then heating it with an infrared heater at 190°C for 2 minutes to fuse the tape.
The suitability of the taping was also good (〇), and the finished surface had a good gloss. As shown in the evaluation results in Table 2, the thermal adhesion was also good, and the tapes adhered well not only to each other but also to the steel pipe and were integrated. The crack resistance and cold resistance were also good, and the heat resistance tested at 110°C was also good. Thus, it has been found that the product of the present invention can be used as the exterior of flexible steel pipes for water supplies and instantaneous water heaters for purposes such as heat retention and rust prevention. On the other hand, as a comparative example, No. 8 using a nonwoven fabric with a fineness of 15 denier had large unevenness due to fibers on the surface after thermal bonding, the gloss was unsatisfactory, and the adhesion strength, crack resistance, and cold resistance were all rejected. It was hot. Polymer A with a melting point of 200°C was used.
No. 9 had insufficient thermal adhesion and the tapes did not adhere to each other. In addition, when the bonding temperature was raised to 240°C to achieve sufficient adhesion, the material foamed and the surface became pockmarked, resulting in a poor appearance, making it unsuitable as a thermoadhesive composite material. Example 3 Fineness 5 denier and basis weight 50 used in Example 1
g/m ² long fiber nonwoven fabric and polymer No.A of Example 2
Polymer No. A-5 with 0.4 wt% of carbon black and 0.3 wt% of hindered amine weathering agent “Sanol” LS 770 (manufactured by Ciba Geigy) was added to Polymer No. A-2 with a thickness of 150 μm on one side in the same manner as in Example 1. Composite material No. 10 was made in which some nonwoven fibers were visible. Slit this to a width of 50mm to make tape.
A simulated steel strip with a diameter of approximately 50 mm is taped with 1/2 wrap on a steel strip for an armored cable, and heated with an infrared heater at 200℃ for 2 minutes to fuse and create a black shiny cable coating layer. was formed. When the coating layer was cut open and the adhesion was examined, it was found that the tapes adhered to each other, and the steel strips also adhered moderately. It was superior to conventional melt extrusion coating methods in that there was no Cold resistance, heat resistance, and crack resistance were also good (○). For comparison, a similar composite material (No. 11) was prepared using a short fiber nonwoven fabric (using a wet binder, basis weight 50 g/m ² ) made by a wet method using PET short fibers of 5 denier and a fiber length of 30 mm. When the crack resistance was examined, it was found that because short fibers were used, the cut end was wide and was rated as △ to (x). Even in the heat resistance test, some resin flow was observed. Thus, it was found that long fiber nonwoven fabrics are suitable as nonwoven fabrics, and short fiber nonwoven fabrics cannot be used. Example 4 Polymer B was PBT-PTMG (PTMG60wt
%, melting point 170℃, PTMG molecular weight 1000) with carbon black 0.4wt% and "Sanol" LS770 0.3wt% added, and in the same manner using the long fiber nonwoven fabric used in Example 3, a 150μ thick sheet was prepared. A composite material (No. 12) was made and evaluated in the same manner as in Example 3.
Although the tapes had good adhesion to each other, they were not substantially adhered to the steel strip and could be easily peeled off from the steel strip. It also had good cold resistance, heat resistance, and crack resistance. It has thus been found that the use of Polymer B is preferred when metal adhesion is not required. Example 5 Same as Example 1, fineness 5 denier, basis weight
A 100 g/m ² long fiber nonwoven fabric (thickness approximately 0.2 mm) was made. Prepare No. A-1 (used in Example 1) as Polymer A, melt-extrude it using the extrusion laminator of Example 1, and adjust the pressure of the press roll to make Polymer A approximately half the thickness of the nonwoven fabric. A composite material impregnated with The total thickness was approximately 300μ. This composite material was formed into a tape with a width of 12 mm, which was then taped onto a flexible steel pipe with a diameter of 13 mm so that the non-woven fabric surface became the steel pipe surface, and then heated with an infrared heater at 200°C for 2 minutes.
The tape was fused. The finished coated steel pipe had a glossy surface and cushioning properties. Adhesion between the tapes was good (Good), and cold resistance, heat resistance, and crack resistance were all good (Good). Thus, it was found that a composite material made by partially burying a nonwoven fabric in Polymer A has cushioning properties and heat retention properties.

Claims (1)

[Claims] 1 A polyether ester copolymer composed of a polyether segment and a polyester segment and having a melting point of 110 to 180°C, and a long fiber nonwoven fabric with a fabric weight of 20 to 300 g/m ² consisting of long fibers with a fineness of 1 to 10 denier. A thermoadhesive composite material characterized by being integrated.