JPH0665487A - Flame-retardant sheet and thermoformed article - Google Patents

Abstract

PURPOSE:To provide a formed article produced by the deep draw forming of a polybutylene terephthalate sheet having excellent flame-retardancy and thermoformability. CONSTITUTION:The objective sheet is produced by compounding (A) 60-90 pts.wt. of polybutylene terephthalate with (B) 1-20 pts.wt. of a polyarylate and/or polyester elastomer, (C) 5-25 pts.wt. of a flame-retardant consisting of a bromine compound, (D) 0-15 pts.wt. of a flame-retarding assistant consisting of an antimony compound and (E) <=2wt.% (based on the sum of A to D) of fine powder of polytetrafluoroethylene. A thermoformed article is produced by forming the sheet under heating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet mainly composed of polybutylene terephthalate, which is excellent in flame retardancy and thermoformability, and a molded article obtained by thermoforming using this sheet.

[0002]

Sheets made of polybutylene terephthalate are generally difficult to thermoform. Also, polybutylene terephthalate is easy to burn, especially when made into a thin sheet.

The present invention is intended to impart thermoformability and flame retardancy to such polybutylene terephthalate at the same time.

Accordingly, the present invention relates to the development of a new material for deep drawing a polybutylene terephthalate sheet.

[0005]

The present invention comprises: (A) 60 to 90 parts by weight of polyethylene terephthalate, (B) polyarylate or /
And 1 to 20 parts by weight of polyester elastomer, (C)
5 to 25 parts by weight of brominated polystyrene, 0 to 15 parts by weight of (D) antimony compound, and (E) fine powdered fluororesin 0 to the total amount of (A), (B), (C) and (D) ~ 1
A resin composition obtained by kneading wt% (PHR) is formed into a sheet. Further, by thermoforming such a sheet, a thermoformed article excellent in flame retardancy is obtained.

The present invention will be described in detail below.

The polybutylene terephthalate (A) used in the present invention is a polyester containing terephthalic acid as an acid component and butylene glycol as a glycol component.
It does not matter that a dicarboxylic acid other than terephthalic acid and / or an oxycarboxylic acid or a glycol component other than butylene glycol is contained in a small amount, for example, 10 mol% or less, preferably 5 mol% or less.

Aromatic dicarboxylic acids other than terephthalic acid,
For example, phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenylmethane dicarboxylic acid, diphenyl ketone dicarboxylic acid, diphenyl sulfide dicarboxylic acid, diphenyl sulfone dicarboxylic acid, aliphatic dicarboxylic acid, for example, Examples thereof include succinic acid, adipic acid, sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, tetralindicarboxylic acid and decalindicarboxylic acid.

As the glycol component, ethylene glycol, propylene glycol, trimethylene glycol,
Pentamethylene glycol, hexamethylene glycol, octamethylene glycol, neopentyl glycol, cyclohexanedimethanol, xylylene glycol, diethylene glycol, polyethylene glycol,
Examples include bisphenol A, catechol, resorcinol, hydroquinone, dihydroxydiphenyl, dihydroxydiphenyl ether, dihydroxydiphenylmethane, dihydroxydiphenylketone, dihydroxydiphenylsulfide, dihydroxydiphenylsulfone and the like.

Examples of the oxycarboxylic acid component include oxybenzoic acid, hydroxynaphthoic acid, hydroxydiphenylcarboxylic acid and ω-hydroxycaproic acid.

Further, trifunctional or higher functional compounds such as glycerin, trimethylpropane, pentaerythritol, trimellitic acid and pyromellitic acid may be copolymerized within a range in which the polyester does not substantially lose the molding performance.

Such a polyester can be obtained by polycondensing terephthalic acid and / or a functional derivative thereof and butylene glycol and / or a functional derivative thereof by a conventionally known aromatic polyester production method. The terminal carboxyl group concentration of PBT used in the present invention is not particularly limited, but it is desirable that the concentration is low.

The component (B) polyarylate resin used in the present invention is represented by the following general formula (Formula 1).

[0014]

[Chemical 1]

It is obtained from a bisphenol compound represented by and an aromatic dicarboxylic acid, wherein --X
— Is one of —O—, —S—, —SO ₂ —, —CO—, and an alkylene group, and R _{1 to} R ₈ are hydrogen and have 1 carbon atom.
~ 8 alkyl group or halogen.

Examples of the bisphenol compound represented by the general formula (Formula 1) include 4,4'-dihydroxy-diphenyl ether, bis (4-hydroxy-2-methylphenyl) ether, and bis (4-hydroxy-3-chlorophenyl) ether. , Bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3,5) -Dichlorophenyl) methane, bis (4
-Hydroxy-3,5-dibromophenyl) methane,
1,1-bis (4-hydroxyphenyl) ethane, 2,
2-bis (4-hydroxyphenyl) propane, 2,2
-Bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3,5)
-Dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 1,
1-bis (4-hydroxyphenyl) butane, bis (4
-Hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -4'-methylphenylmethane, 1,
1-bis (4-hydroxyphenyl) -2,2,2-trichloroethane, bis (4-hydroxyphenyl)-
(4'-chlorophenyl) methane, 1,1-bis (4-
Hydroxyphenyl) cyclohexane, 1,4-bis (4-hydroxyphenyl) cyclohexane, 2,2-
Examples thereof include bis (4-hydroxynaphthyl) propane, and 2,2-bis (4-hydroxyphenyl) propane is particularly preferable. Further, these bisphenol compounds may be a mixture of two or more kinds, and further other divalent compounds such as 2,2'-dihydroxydiphenyl, dihydroxynaphthalene, hydroquinone, resorcinol, 2,6-
A mixture with dihydroxychlorobenzene, 2,6-dihydroxytoluene, 3,6-dihydroxytoluene and the like may be used.

The aromatic dicarboxylic acid is preferably terephthalic acid, isophthalic acid, or a mixture thereof. Further, these terephthalic acid and isophthalic acid may be substituted with halogen or an alkyl group having 1 to 8 carbon atoms.
In addition to these, a small amount of other aromatic or aliphatic dicarboxylic acid or its functional derivative may be copolymerized.

The polyester elastomer used in the present invention is generally composed of an aromatic dicarboxylic acid component (1), a low molecular weight glycol component (2) having 3 or more carbon atoms and a polyoxyalkylene glycol component (3). From the viewpoint of heat resistance, 70 mol% or more is preferably composed of one type of dicarboxylic acid component.

As the component (1), terephthalic acid,
Isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,
7-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4′-diphenyletherdicarboxylic acid, 4,4′-diphenylsulfonedicarboxylic acid, 4,
Although 4'-diphenoxyethanedicarboxylic acid and the like can be considered, terephthalic acid and 2,6-naphthalenedicarboxylic acid are particularly preferable. These dicarboxylic acids may be used alone or in combination of two or more.

As the component (2), an aliphatic glycol having 3 or more carbon atoms such as tetramethylene glycol or hexamethylene glycol is preferably used, and bishydroxyethoxy bisphenol A or 4,4'-bishydroxyethoxydiphenyl sulfone. Also used are glycols having an aromatic group such as and glycols having an alicyclic group such as cyclohexanedimethanol.

As the component (3), polyoxypropylene glycol, poly-1,2-butylene ether glycol, polyoxytetramethylene glycol, polyoxypentamethylene glycol, polyoxyhexamethylene glycol, polyoxyheptamethylene glycol, poly Oxyoctamethylene glycol, polyoxynonamethylene glycol and the like are considered. Of these, polyoxytetramethylene glycol is particularly preferable. As these polyoxyalkylene glycols, not only copolymerized ones but also random and block copolymerized ones can be used.

The total amount of the (B) polyarylate or polyester elastomer used in the present invention is 1 to 20 parts by weight, preferably 5 to 15 parts by weight. The component (B) is effective in imparting excellent thermoformability to the sheet.

Examples of the flame retardant (C) composed of a bromine compound used in the present invention include brominated bisphenol A type polycarbonate, brominated epoxy, brominated polystyrene, brominated imide and brominated diphenyl ether.

The brominated epoxy flame retardant used in the present invention has the following structure (II).

[Chemical 2]

The brominated polystyrene flame retardant used in the present invention has the following structure (III):

[Chemical 3]

The brominated imide flame retardant used in the present invention has the following chemical formula (IV).

[Chemical 4]

The brominated diphenyl ether flame retardant used in the present invention has the following chemical formula (V).

[Chemical 5]

The flame retardant used in the present invention is added in an amount of 5 to 5.
25 parts by weight. The larger the amount of the inorganic filler added in the whole composition, and the smaller the amount of the flame retardant added when a flame retardant aid such as Sb ₂ O ₃ is used together, but at least 5
Parts by weight are necessary, and if the amount is less than that, the flame retardancy of the resulting composition is insufficient. On the contrary, when the amount is more than 25 parts by weight, the flame retardant is poorly dispersed, so that the extrudability and the moldability are deteriorated, and the strength of the obtained molded product is lowered, which is not preferable.

The flame retardant may be used alone or in combination of two or more. However, the total amount of the flame retardants used must be within the range of 5 to 25 parts by weight.

Next, Sb used in the present invention₂O₃as well as/
Or xNa₂O / Sb₂O_Five・ YH ₂O (x = 0 to 1,
The flame retardant aid (D) represented by y = 0 to 4) has a flame retardant effect.
It is preferable to add it in order to improve it. Limited particle size
However, 0.02 to 5 μm is preferable.

If necessary, it may be surface-treated with an epoxy compound, a silane compound, an isocyanate compound, a silane compound, a titanate compound, or the like. The amount of the flame retardant aid added is 0 to 15 parts by weight, but when the flame retardant aid is not added, it is necessary to add a large amount of the flame retardant, and therefore, it is preferable to add 20 to 70 parts by weight of the flame retardant. It is advisable to add a combustion aid. On the other hand, if the addition amount is more than 15 parts by weight, the decomposition of the resin or the compounding agent is promoted and the strength of the molded product is lowered, which is not preferable.

Next, the fine powdery polytetrafluoroethylene (E) used in the present invention is produced by emulsion polymerization, and the particle size of the primary particles is preferably 0.05 to 0.5 μm.

A small amount of a monomer such as perfluoroalkyl vinyl ether may be copolymerized with this (E) as long as the flame retardant effect is not impaired. Addition amount is 0-2
It is PHR. By adding the component (E), it becomes difficult for the molten polymer to drip when flame retardant, and thus secondary combustion due to the drip is less likely to occur.

In the polyester resin composition of the present invention, other additives such as an inorganic filler, a colorant, and an ultraviolet absorber are added to the polyester resin composition in order to impart desired properties depending on the purpose, so long as the physical properties are not significantly impaired. , Release agents, antistatic agents and the like can be added.

Next, a method for forming the composition of the sheet of the present invention into a sheet will be described. The sheet of the present invention is a commonly used known equipment and method, that is, an extruder is supplied with the composition or / and components constituting the present invention, the mixture is extruded through a slit-shaped die, cooled on a casting drum, and solidified. It is obtained by forming a sheet at least.

The method of feeding the composition and / or the components of the present invention to the extruder is, for example, after mixing the components,
Melt kneading and extruding with an extruder to adjust pellets, and then using the pellets to prepare a sheet, once preparing pellets having different compositions, mixing the pellets in a predetermined amount, and supplying the pellet-forming extruder. Any method such as a method of obtaining a sheet and a method of directly charging one or more of each component into an extruder for making a sheet can be used.
In addition to the above, a sheet and / or a thermoformed product and / or a product obtained by crushing scraps generated during thermoforming to be flakes are also used as one of the materials or components in the sheet formation of You can also do it. Further, it is preferable that a part of the components is made into fine powder and the other components are mixed and added in order to uniformly mix these components. In addition,
It is preferred to dry the pellets and ingredients prior to feeding them to the extruder.

As a method of drying the pellets, for example, a temperature in the range of 100 ° C. or higher and a temperature of 30 ° C. lower than the melting point of polyester, more preferably a temperature in the range of 120 ° C. or higher and 50 ° C. lower than the melting point of polyester. A method of drying by using dehumidified air or nitrogen gas or the like heated to the above, a method of drying by using electromagnetic waves, and the like are applied.

During casting, a film or sheet having excellent flatness can be obtained by applying static electricity to the film or sheet so that the film or sheet is brought into close contact with the cooling drum.

The sheet of the present invention obtained as described above may be cut and used as it is without being subjected to thermoforming, but thermoforming of the sheet can be utilized for various purposes.

The film or sheet obtained as described above is preheated by an infrared heater, a hot plate heater, hot air or the like, and then subjected to thermoforming.

As a thermoforming method, a female mold, or a female mold and a male mold or a plug is used, and for example, vacuum molding, pressure molding or vacuum pressure molding is adopted. During molding, the female mold, male mold and plug can be heated.

[0042]

[Application] The flame-retardant sheet obtained by the present invention and a thermoformed article made of this sheet are, for example, electrical and electronic equipment parts, OA equipment parts, mechanical parts such as electric tools, insulating materials such as motors, and card materials. It is usefully used as a base material, a building material, etc., but its use is not particularly limited.

[0043]

EXAMPLES AND COMPARATIVE EXAMPLES The present invention will be described in detail below with reference to Examples and Comparative Examples. The flame retardancy and moldability of the sheet according to the present invention were evaluated as follows.

Flammability: According to the method of Subject 94 (UL-94) of Underwriters Laboratories,
The flammability was tested using 5 test pieces, and the flammability grade was evaluated according to UL-94.

Thermoformability: FC-1APA manufactured by Asano Laboratory
Evaluation was performed by mounting a tray-shaped mold on a W-type vacuum pressure molding machine, molding, and observing the molding state.

Resin composition twisted pellets prepared by melt-kneading the composition shown in Table 1 were prepared.
After drying at 30 ° C. for 5 hours, it was melt-extruded into a sheet. The sheet thickness was 0.3 mm.

Next, the flammability and thermoformability of the sheet were evaluated, and the results are summarized in Table 2.

The components used in the examples and comparative examples are as follows. (A) Polyethylene terephthalate (PET) (B) Polyarylate (PAr) Polyester elastomer (Ela) (C) Brominated polystyrene (Br-modified PSt) Brominated bisphenol A type polycarbonate (Br-modified PC) Brominated epoxy (Br-modified Epx) ) (D) Antimony trioxide (Sb.O) Sodium antimonate (Sb.Na) (E) Fine powder polytetrafluoroethylene (PPTFE)

[0049]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08L 67/03 LNZ 8933-4J // C08J 5/00 CFD 7016-4F

Claims (2)

[Claims] 1. (A) Polyethylene terephthalate 60
To 90 parts by weight, (B) polyarylate or / and polyester elastomer 1 to 20 parts by weight, (C) bromine compound-containing flame retardant 5 to 25 parts by weight, (D) antimony compound-containing flame retardant aid 0 to 15 A flame-retardant sheet made of a composition containing (E) 0 to 2% by weight of finely powdered polytetrafluoroethylene with respect to parts by weight and the total amount of the components (A) to (D). 2. A thermoformed article formed by heating the flame-retardant sheet according to claim 1.