JP3292232B2 - Interphase insulator, composite rod used for the same, and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-phase insulator (also referred to as "inter-phase insulating paper") for insulating a plurality of windings wound around a stator core of a motor such as a compressor of a refrigerator or an air conditioner. More particularly, the present invention relates to an interphase insulator for insulating a plurality of phase windings wound around a stator core of a motor such as a refrigerator or an air conditioner compressor using an alternative Freon, a composite rod used therefor, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an inter-phase insulating film made of polyethylene terephthalate has been used as a material for insulating between windings of a plurality of phases wound around a stator core of a compressor motor of a refrigerator, a freezer, an air conditioner or the like. Were used as synthetic rods made of the same raw material. Motors using these are immersed in the refrigerant or used in contact with the refrigerant.

As refrigerants, Freon 11, 12, 114,
When No. 115 or the like was used, there was no particular problem in the performance of the product even if the interphase insulating paper used was one connected with a film made of ordinary polyethylene terephthalate and a rod made of monofilament.

[0004] However, the above-mentioned conventional chlorofluorocarbon has a risk of destructing the ozone layer of the earth and deteriorating the environment. Therefore, its use has been regulated by laws and voluntary regulations of the industry. These alternative CFCs include CFC 1
Mixed refrigerants such as 34a (ozone destruction coefficient 0), Freon 22 (ozone destruction coefficient 0.05), and 407c are being studied.

[0005]

However, when a conventional film made of polyethylene terephthalate and a synthetic rod made of a monofilament are used as a refrigerant using these alternative fluorocarbons as a refrigerant, monomers and oligomers existing inside the film or the monofilament can be used. Is extracted by the refrigerant, thereby causing foreign matter clogging such as capillary clogging that evaporates the refrigerant, causing a problem of lowering the refrigerant performance. Under such circumstances, there is a demand for the development of an interphase insulating paper that exhibits the same performance as the conventional one even when the alternative fluorocarbon is used, and in particular, the development of a synthetic resin rod that connects the upper and lower films.

[0006] In response to these demands, the development of films has been preceded, and various materials have been developed. This material can be punched into a predetermined shape and used as an interphase insulating film. However, this type of method has a low yield of the film material,
There was a problem that the cost was high.

The present invention has been made in view of the above circumstances, and is suitable as a substitute for chlorofluorocarbons. It does not reduce electrical insulation, does not cause foreign matter to be clogged with a capillary that vaporizes the refrigerant, and further reduces the cost. An object of the present invention is to provide a low interphase insulator, a composite rod used for the same, and a method of manufacturing the same.

[0008]

In order to achieve the above object, an interphase insulator according to the present invention comprises at least two synthetic resin films having a melting point of more than 260 ° C. connected at a plurality of locations by synthetic rods. The synthetic rod is a polyethylene-2,6-naphth having a melting point exceeding 260 ° C.
Made of polyester with tallate as the main component, straight
Monofilament subjected to chemical heat treatment , tensile strength is 2.0 g / d or more, knot strength is 1.0 g / d or more, methanol extraction is 0.10% by weight or less, chloroform extraction is 0.50% by weight or less der is, and the synthetic
The resin film and the synthetic rod are heated by high-frequency heating.
It is characterized by being fused and connected .

In the interphase insulator of the present invention, the synthetic resin film is preferably a polyester containing polyethylene-2,6-naphthalate as a main component.

Next, the synthetic rod of the present invention has at least two
A synthetic rod used for an interphase insulator in which a plurality of synthetic resin films each having a melting point exceeding 260 ° C. are connected,
The synthetic rod is a polyethylene whose melting point exceeds 260 ° C.
Polyester containing -2,6-naphthalate as the main component
It is composed of a monofilament drawn yarn that has been subjected to a linearized heat treatment, and has a tensile strength of 2.0 g / d or more, a knot strength of 1.0 g / d or more, an extraction amount of methanol of 0.10% by weight or less, and an extraction amount of chloroform. 0.50% by weight or less. The synthetic rod preferably has a diameter of 0.4 to 1.0 mm, more preferably 0.80 to 0.95 mm. In a special case, the one near 0.5 mm may be used.

Next, a method of manufacturing a synthetic rod according to the present invention is a method of manufacturing a synthetic rod used for an interphase insulator, wherein a polymer having polyethylene-2,6-naphthalate as a main component is melt-spun, and is heated to 40 ° C. or higher. After cooling and solidifying in a liquid of 80 ° C. or less, 2.5
The monofilament was stretched in the range of 6.0 times, if
Fusion bonding of synthetic resin film and synthetic rod by high frequency heating
Before heating the monofilament to at least 120 ° C.
The straightening heat treatment is performed at the above temperature . In the above method, before the synthetic resin film and the synthetic rod are fused by high-frequency heating, the monofilament is unwound and subjected to the linearization heat treatment at a temperature of at least 120 ° C. in order to correct the curl.

According to the interphase insulator of the present invention, it can be suitably used as a substitute for chlorofluorocarbon, does not reduce the electrical insulation, does not cause foreign matter to be clogged by capillary clogging of the refrigerant, and further reduces the cost. Can also be lower.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the constitution of the present invention, it is required to be made of synthetic resin and have a melting point exceeding 260 ° C. This is because the alternative fluorocarbon refrigerant tends to be more thermally and chemically stable than the conventional refrigerant, and the synthetic rod is required to have higher heat resistance. Among these resins, polyethylene-2,6-naphthalate having a melting point of 273 ° C., polyarylate consisting of p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid having a melting point of 270 ° C., and a thermal decomposition temperature of Aramids such as polyparaphenylene terephthalamide at 371 ° C .; Further, polyethylene terephthalate having a melting point of 258 to 260 ° C. is not preferable as described in the section of the prior art.

Next, in the present invention, the tensile strength is 2.0
g / d or more, and the knot strength must be 1.0 g / d or more. This is required from the viewpoint of the process of inserting the interphase insulating paper inside the motor and the durability. Below these values, even if other properties are excellent, they cannot be provided from a practical point of view. The synthetic rod of the present invention easily achieves the strength required for the synthetic rod from a practical point of view, for example, 8 kg or more.

For the measurement of the amount of methanol extracted, after the synthetic rod is absolutely dried, the weight is measured to four decimal places (this weight is designated as A), and the extraction is performed for 4 hours in boiling methanol at normal pressure. . Then, after washing with fresh methanol, drying (absolute drying), the weight is measured to four decimal places (this weight is B), and the amount of methanol extracted is measured by the following equation.

[0016]

## EQU1 ## Methanol extraction amount (% by weight) = ｛(AB) /
A｝ × 100

In order to measure the chloroform extraction amount, the synthetic rod is washed with petroleum ether to remove adhering impurities and oils, and then dried (absolutely dried), and the weight is measured to four decimal places (this weight is used). A), and extraction is carried out in boiling chloroform at normal pressure for 8 hours. Thereafter, the product is washed with fresh chloroform and then dried (absolutely dried). The weight is measured to four decimal places (this weight is defined as B), and the amount of chloroform extracted is determined by the following formula.

[0018]

## EQU2 ## Chloroform extraction amount (% by weight) = ｛(AB)
/ A｝ × 100

Most of the components extracted by methanol are oils and other impurities attached to the surface of the synthetic rod. In particular, the former causes a leak current.

If a nonionic or cationic surfactant is contained in the oil component, the occurrence of a leak current becomes extremely large. However, the amount of synthetic rods extracted was 0.
It has been found that when the content is 10% by weight or less, generation of a problematic leak current can be controlled.

On the other hand, most of the components extracted with chloroform are occupied by monomers and oligomers contained inside the synthetic rod. If the chloroform extraction amount exceeds 0.50% by weight, these contents are extracted into alternative Freon and cause foreign matter clogging in the capital that vaporizes the refrigerant. It turned out not to be allowed.

Even if the amount of methanol extraction is 0.10% by weight or less, if the amount of chloroform extraction exceeds 0.50% by weight,
Although the generation of leak current can be controlled, the generation of foreign matter clogging in the capillary cannot be controlled. Conversely, if the amount of chloroform extraction is 0.50% by weight or less and the amount of methanol extraction exceeds 0.10% by weight, the clogging of foreign matter in the capital can be controlled, but the generation of leak current cannot be controlled.

By simultaneously satisfying the two characteristics of an extraction amount of methanol of 0.10% by weight or less and an extraction amount of chloroform of 0.50% by weight or less, a synthetic rod suitable as a substitute for chlorofluorocarbon can be obtained for the first time. And the synthetic rod of the present invention having the above characteristics can be efficiently manufactured by the method described below. First, when melt-spinning the above polyester, ordinary conditions using an extrusion spinning machine can be adopted. For example, polymer temperature 260-350 ° C, extrusion pressure 10-500 kg / cm
^2. Cap diameter 0.1-5mm, spinning speed 3-100m /
min. Such conditions can be appropriately selected.

The polyester resin to be melt-spun may contain, for example, pigments, dyes, light stabilizers, ultraviolet absorbers, antioxidants, plasticizers and the like. The spun monofilament is cooled in a bath after passing through a short gas zone. Here, a liquid inert to the polyester, for example, water is usually used as the refrigerant. The cooling temperature is
It needs to be cooled and solidified in an inert liquid at 40 to 80 ° C. If the cooling is performed at a temperature higher than that, the stretchability in the next step may be hindered.

The cooled and solidified monofilament is sent to a stretching step. As a stretching and heat setting atmosphere, for example, a heated heat medium bath such as polyethylene glycol, glycerin, silicone oil, or a dry hot gas is used. The most important thing in this step is that the temperature of the heated heating medium bath, the dry hot gas and the like is 120 ° C. or higher. In conventional polyethylene terephthalate, nylon and other general resins, a warm water bath (60 to 90
° C) has been used. In the present invention, the stretching is performed in a heating atmosphere at 120 to 250 ° C., which is much higher than that of a conventional hot water bath. If it is lower than 120 ° C., it is difficult to perform practical stretching. On the other hand, under an atmosphere at a temperature exceeding 250 ° C., the yarn becomes soft and the yarn hangs down by its own weight, making it difficult to draw.

When stretching, the stretching ratio is set to 2.5.
Double to 6.0 times. This magnification may be multi-stage stretching divided into two or three stages, but the physical properties of the present invention can be achieved even by one-stage stretching. When the ratio exceeds 6.0 times, the resins used in the present invention are all rigid and undesirably exhibit defects such as vertical cracks (fibrillation). On the other hand, when the ratio is less than 2.5 times, the tensile strength and the knot strength of the obtained synthetic rod are undesirably low.

After the stretching, an appropriate constant length or relaxation heat treatment can be performed for the purpose of removing stretching strain and the like, if necessary. The tensile strength and knot strength in the present invention are measured according to JIS L1013 and the like.

[0028]

The present invention will be described more specifically with reference to the following examples. The present invention is not limited by the following examples. (Example 1) An intrinsic viscosity of 0.931 dl / g containing 0.07% by weight of titanium oxide having an average particle size of 0.10 µm.
(Measured at 25 ° C. using o-chlorophenol as a solvent)
The polyethylene-2,6-naphthalate pellets of
Dry at 150 ° C. for 5 hours. Then, it was melt-spun at 300 ° C. using a die having two holes and a hole diameter of 3.5 mm, and then rapidly cooled and solidified in hot water at 60 ° C. to obtain an undrawn monofilament yarn.

Next, the undrawn monofilament yarn was
Under an atmosphere of 20 ° C., the film is stretched 4.3 times to have a diameter of 0.8.
A 94 mm monofilament drawn yarn was obtained. The obtained monofilament drawn yarn was wound up without applying the original oil agent. The tensile strength of this monofilament is 2.8 g /
d, knot strength was 1.1 g / d, and tensile elongation was 8.9%.

The monofilament drawn yarn obtained had a methanol extraction of 0% and a chloroform extraction of 0.3%.
8%. This was subjected to a linearization heat treatment at a temperature of 130 ° C. for 0.5 seconds, and cut into a predetermined length (95 mm).
Next, as shown in FIG. 1, the biaxially stretched films 2 and 3 made of polyethylene-2,6-naphthalate having a thickness of 30 μm punched as shown in FIG. 5 and were continuously welded and joined by using a high-frequency welding device (also called an “ultrasonic welding device”). Reference numerals 6a to 6d denote welding joints.
The welding and joining conditions of the high frequency welding apparatus are as follows: frequency: 70M
Hz, power: 3 kW, pressure: 3.5 kg / cm ² . FIG. 1 shows a plan view of an interphase insulator (interphase insulating paper) 1.

In order to measure the weld joint strength, the upper and lower films were pulled in a direction in which they were separated from each other, and the tensile strength was measured. As a result, it was 8 kg or more, the film was broken on the film surface, and no damage was found on the synthetic rod. A compressor incorporating a motor using the interphase insulating film obtained in this way was mounted, and a refrigerator using Freon 22 as a refrigerant was operated for several months. No current was generated and no problems occurred.

(Comparative Example 1) A synthetic rod was prepared under the usual conditions except that polyethylene terephthalate was used as a raw material. Diameter 0.910mm, tensile strength 4.9g /
d, knot strength was 4.0 g / d. The methanol extraction was 0.34%, and the chloroform extraction was 1.
36%.

When the raw material was wound without applying the oil agent, the methanol extraction amount was 0.04% and the chloroform extraction amount was 1.34%. In practical tests, the former was poor in both leak current and clogging of the capillary, and the latter was poor in clogging of the capillary.

[0034]

As described above, according to the interphase insulator (interphase insulating paper) of the present invention and the synthetic rod used for the same, a monofilament composed mainly of a synthetic resin having a melting point exceeding 260 ° C. , Tensile strength is 2.0
g / d or more, knot strength is 1.0 g / d or more, methanol extraction is 0.10% by weight or less, and chloroform extraction is 0.50% by weight or less. It is possible to provide an interphase insulating paper which does not cause clogging of foreign matter in a capillary for evaporating a refrigerant without causing the clogging. Therefore, the chlorofluorocarbons 134a, 134a, 12
It can be suitably used for refrigerators, freezers, air conditioners, and the like that use refrigerants such as 3, 141b, 22, 142b, and 152a as alternative refrigerants. Also, when inserting the interphase insulating paper into the motor, the work can be efficiently and rationally performed, and can be provided at a low cost.

[Brief description of the drawings]

FIG. 1 is a plan view of an interphase insulator (interphase insulating paper) obtained in Example 1 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Interphase insulating material (interphase insulating paper) 2,3 Biaxially stretched film made of polyethylene-2,6-naphthalate 4,5 Monofilament stretched yarn made of polyethylene-2,6-naphthalate 6a-6d Welded joint

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-131012 (JP, A) JP-A-9-135555 (JP, A) JP-A-8-7650 (JP, A) 66542 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 15/10 H02K 3/30 H02K 3/34

Claims (4)

(57) [Claims] 1. An interphase insulator in which at least two synthetic resin films having a melting point of more than 260 ° C. are connected at a plurality of positions by synthetic rods, wherein said synthetic rod is a polyethylene having a melting point of more than 260 ° C.
Polyester containing -2,6-naphthalate as the main component
Consisting of monofilaments that have been subjected to a linearized heat treatment , with a tensile strength of 2.0 g / d or more and a knot strength of 1.0 g
/ D or more, the methanol extraction amount is 0.10% by weight or less, and the chloroform extraction amount is 0.50% by weight or less.
And the synthetic resin film and the synthetic rod are high in height.
An interphase insulator which is fused and connected by frequency heating . Wherein said synthetic resin film of polyethylene -
The interphase insulator according to claim 1, which is a polyester containing 2,6-naphthalate as a main component. 3. A synthetic rod used for an interphase insulator in which at least two synthetic resin films having a melting point of more than 260 ° C. are connected at a plurality of positions, wherein the synthetic rod has a melting point of 2 or more.
Polyethylene-2,6-naphthalate exceeding 60 ° C
It is composed of polyester as the main component and is heat-treated for linearization.
It consists of a monofilament drawn yarn, the tensile strength of 2.
A synthetic rod having a knot strength of at least 0 g / d, a knot strength of at least 1.0 g / d, a methanol extraction of at most 0.10 wt%, and a chloroform extraction of at most 0.50 wt%. 4. A method for producing a synthetic rod used for an interphase insulator, comprising: spinning a polymer containing polyethylene-2,6-naphthalate as a main component; and cooling and solidifying the polymer in a liquid at 40 ° C. or higher and 80 ° C. or lower. Then, it is stretched in a heating atmosphere of 120 to 250 ° C. in a range of 2.5 to 6.0 times to obtain a monofilament, and the synthetic resin film and the synthetic rod are rotated at a high speed.
Before welding by wave heating, reduce the monofilament
A method for producing a synthetic rod, comprising performing a linearization heat treatment at a temperature of at least 120 ° C.