JPH0794570B2 - Flame-retardant thermoplastic polyester resin foam composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant composition for thermoplastic polyester resin foams.

(Prior Art) A thermoplastic polyester resin (hereinafter referred to as PAT) has excellent properties not found in polyethylene or polystyrene. For example, PAT has high rigidity, good shape stability, and excellent heat resistance to withstand 200 ° C. Therefore, it was attempted to use PAT as a building material or a structural member.

The biggest problem with this scheme is that PAT is an organic substance, especially an ester, and is easily burned.
Therefore, an attempt has been made to make PAT flame-retardant so that PAT can be used as a building material or a structural member.

However, PAT cannot be easily made flame-retardant like polyethylene and polystyrene. It ’s a PAT,
This is because it has a much higher softening point than polyethylene or polystyrene. In other words, polyethylene and polystyrene can easily be made flame-retardant by mixing various halogen compounds, but when trying to mix various halogen compounds similar to PAT, the halogen compounds decompose at the melting temperature of PAT. As a result, not only the flame retarding effect is not brought about, but also the decomposition product of the halogen compound causes the PAT to be colored, resulting in the deterioration of the properties of PAT.

On the other hand, it may be possible to add an inorganic compound to PAT to make it flame-retardant. Inorganic compounds have the advantage of not decomposing, but have poor flame retardant effects, and in order to exhibit sufficient flame retardancy, it is necessary to add a large amount of inorganic compounds.
If a large amount is blended, the properties of PAT will be impaired, and therefore satisfactory flame retardancy could not be obtained. Further, it has been more difficult to make PAT flame-retardant and at the same time suitable for foaming.

(Problems to be Solved by the Invention) The present invention is intended to provide a composition for PAT foam having sufficient flame retardancy while maintaining good characteristics of PAT.

(Means for Solving the Problems) The present inventor made various PAT compounds by adding various compounds to the PAT, and examined the flame retardancy thereof. As a result, the decomposition temperature is 30
When a brominated aromatic compound at 0 ° C or higher and a specific organotin compound are blended in a specific ratio and added to PAT, the characteristics of PAT are not significantly changed, and PAT can be made flame-retardant. It has been found that it is possible to make a foam.
The fact that the characteristics of PAT do not change means that, for example, PAT containing the above-mentioned brominated aromatic compound and organotin compound is
This is because a satisfactory foamed body can be obtained by extrusion foaming as in the case of PAT that does not contain this.

(Summary of the Invention) The present invention comprises 100 parts by weight of PAT, 0.5 to 5 parts by weight of a brominated aromatic compound having a decomposition temperature of 300 ° C. or higher, and 1 to 30% by weight of an alkyl tin laurate or an alkyl with respect to the brominated aromatic compound. It is a gist of a flame-retardant composition for PAT foams, which is characterized by being mixed with tin malate or alkyl tin mercaptide.

(Explanation of each requirement) PAT used in the present invention is a high molecular weight chain ester obtained by reacting an aromatic carboxylic acid with a dihydric alcohol. Such PAT is commercially available. In the present invention, commercially available PAT can be used.

Although terephthalic acid is most often used as the dicarboxylic acid constituting PAT, isophthalic acid and 2,6-naphthalenedicarboxylic acid may also be used. In addition, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, and diphenoxy dicarboxylic acid may be used as the dicarboxylic acid.

On the other hand, ethylene glycol is mainly used as the dihydric alcohol constituting PAT, but trimethylene glycol, tetramethylene glycol, neopentylene glycol, hexamethylene glycol, cyclohexane dimethylol, tricyclodecane dimethylol 2, 2,
2-bis- (4-β-hydroxyethoxyphenyl) propane, 4,4′-bis- (β-hydroxyethoxy)
It is also possible to use diphenyl sulfone or diethylene glycol.

Among the above PATs, those suitable for use in the present invention include polyethylene terephthalate, polybutylene terephthalate, polybutylene terephthalate elastomer,
Examples include amorphous polyester and polycyclohexane terephthalate. The above PATs can be used alone or in combination. Furthermore, the above-mentioned PAT can be used by mixing it with another resin. When other resins are mixed, the amount of the other resins needs to be less than that of PAT.

Since PAT is generally a resin that is easily hydrolyzed at high temperatures, it is desirable to dry it before processing it. For drying, for example, a dehumidifying dryer may be used. In that case, for drying, for example, air with a dew point of -30 ° C
It is enough to heat it to 160 ℃ and expose PAT to this air for about 4 hours.

In the present invention, in order to make PAT flame-retardant, (a) a brominated aromatic compound having a decomposition temperature of 300 ° C. or higher and (b) a specific organotin compound are used. Of these, the brominated aromatic compound (a) is used in a proportion of 0.5 to 5 parts by weight relative to 100 parts by weight of PAT, and (b) the specific organotin compound is (a).
Used in a proportion of 1 to 30% by weight based on the brominated aromatic compound. Among them, the compound (a) is preferably 1 to 4 parts by weight, and the compound (b) is 5 to 20 parts by weight.
Percentage by weight.

The brominated aromatic compound used in the present invention is obtained by brominating an aromatic compound and has a bromine content of 50% by weight or more. It is a bromide of a phenyl alkyl ether, a bromide of an aromatic polymer, a bromide of a phenyl acrylate ester. Specific compounds include decabromodiphenyl oxide, tetrabromophthalic anhydride, tetrabromobisphenol A derivative (for example, Fearguard 7000 or 7500 manufactured by Teijin Chemicals Ltd.), brominated epoxy resin (for example, Bromlite BR-12 manufactured by Hitachi Chemical Co., Ltd.).
8, BR-133, BR-140, BR-156) and so on.

The specific organotin compound used in the present invention is laurate, malate or mercaptide prepared by directly bonding the carbon atom constituting the alkyl group to tin. For example, dibutyltin dilaurate (C ₄ H ₉ ) ₂ Sn (C ₁₁ H ₂₃ C
OO) ₂ , dioctyl tin dilaurate (C ₈ H ₁₇ ) ₂ Sn (C
Alkyl tin laurate such as ₁₁ H ₂₃ COO) ₂ , dibutyl tin malate (C ₄ H ₉ ) ₂ Sn (OOCCH) ₂ , dioctyl tin malate (C ₈ H ₁₇ ) ₂ Sn (OOCCH) _{2 and the} like,
Dibutyltin dodecyl mercaptide (C ₄ H ₉ ) ₂ Sn (SC ₁₂
Alkyltin mercaptides such as H ₂₅ ) ₂ . These compounds have been used as stabilizers for vinyl chloride resins and were generally known to have the effect of preventing decomposition of the resin. However, the fact that this compound has the effect of preventing the decomposition of the brominated aromatic compound used in the present invention is a fact newly found by the present inventor. Among the above examples, it is particularly preferable to use dibutyltin malate.

In this invention, no special consideration is required for blending PAT with a flame retardant. That is, the brominated aromatic compound and the organotin compound may be added first, or may be added simultaneously.

The composition of this invention may have various additives conventionally used therein added thereto. For example, in order to foam it, a small amount of talc powder is added as a cell regulator, or in order to improve the melting property of PAT, two or more acid anhydride groups are contained in one molecule such as pyromellitic dianhydride. Compounds containing or metal compounds of groups I, II and III in the periodic table such as sodium carbonate can be added.
In addition, colorants, antistatic agents, etc. can be added.

(Effect of the Invention) According to the method of the present invention, 100 parts by weight of PAT has a decomposition temperature of 30%.
Since 0.5 to 5 parts by weight of the brominated aromatic compound at 0 ° C. or more and 1 to 30% by weight of the specific organotin compound based on the brominated aromatic compound are blended, the obtained composition is sufficient. It is flame retardant. Further, this composition retains the good characteristics of PAT as it is because only a relatively small amount of an organic compound is added to impart flame retardancy.
This is a great advantage as compared with the case of blending a large amount of an inorganic substance for imparting flame retardancy. Since this composition retains the good characteristics of PAT as it is, it is possible to obtain a good PAT foam having flame retardancy by extruding foam by adding various foaming agents to the composition. it can. In this respect, the method of the present invention is excellent.

Hereinafter, the reason why the composition of the present invention is excellent will be described with reference to Examples and Comparative Examples in the case of forming a foam plate using this composition. In the following, simply “parts” means “parts by weight”.

Example 1 As the PAT, polyethylene terephthalate (manufactured by Teijin Ltd., trade name TR8580) (hereinafter referred to as PET) was used. First, PET was placed in a dehumidifying dryer and dried at 160 ° C for 4 hours while circulating air having a dew point of -30 ° C.

The PET thus dried was used to make a formulation in the following proportions.

PET 100 parts Talc powder 0.6 Pyromellitic anhydride 0.5 Sodium carbonate 0.1 Brominated aromatic compounds (Daiichi Kogyo Seiyaku Co., Pyroguard SR
-400A, decomposition temperature 450 ℃) 2.0 Organotin compound (dibutyltin dimaleate, Sankyo Co., Stan RC-5R) 0.2 Put the above compound into an extruder with a diameter of 65mm, L / D of 35,
The screws were mixed well at a screw rotation speed of 25 rpm and a barrel temperature of 270 to 290 ° C., and butane as a foaming agent was injected at a rate of 3 wt% from the middle of the barrel.

Thus, PET containing the foaming agent was extruded in a flat plate shape from the flat mold. The mold had a slit length of 65 mm and a slit width of 1 mm and was maintained at 265 ° C. PE extruded into the atmosphere
The T foamed immediately upon exiting the mold. The foamed PET plate was immediately sandwiched between cooling metal plates and allowed to proceed while being in close contact with the cooling metal plate. Thus, the width is 150 mm and the thickness is 20 m.
A foam plate having m and a density of 0.070 g / cc was obtained.

The flame retardancy of this foam plate was examined. Flame retardance is JIS K
The oxygen concentration index specified by 7201 is used. It is recognized that the larger the oxygen concentration index is, the better the flame retardancy is, and if the oxygen concentration index is 26 or more, the flame retardancy is good. Since the oxygen concentration index of this foamed plate was 28.0%, it was confirmed that the flame retardancy was good.

Example 2 A foam plate was produced in the same manner as in Example 1 except that 1 part of Pyrogart SR-250 (decomposition temperature 450 ° C.) was used instead of Pyroguard SR-400A. The foam plate thus obtained had a width of 150 mm, a thickness of 20 mm and a density of 0.070 g / cc. About this foam board, Example 1
When the flame retardancy was examined by the same method as above, the oxygen concentration index was 2
Since it was 7.5%, the flame retardancy was confirmed to be good.

Example 3 In the same manner as in Example 1, except that 0.2 part of dibutyltin dilaurate (KS-22 manufactured by Kyodo Chemical Co., Ltd.) was used as the organotin compound in place of dibutyltin dimaleate. To produce a foam board. The foam plate thus obtained had a width of 150 mm, a thickness of 20 mm and a density of 0.070 g / cc. When the oxygen concentration index of this foamed plate was measured in the same manner as in Example 1, the oxygen concentration index was 28.0%, so it was confirmed that the flame retardancy was good.

Comparative Example 1 A foam plate was produced in the same manner as in Example 1 except that the brominated aromatic compound and the organotin compound were not used. The foam plate thus obtained had a width of 150 mm, a thickness of 20 mm and a density of 0.070 g / cc. About this foam board, Example 1
When the oxygen concentration index was measured in the same manner as above, the oxygen concentration index was 20.0%, so it was recognized that the flame retardancy was inferior.

Comparative Example 2 A foam plate was produced in the same manner as in Example 1 except that the organotin compound was not used.
The obtained foam plate has a width of 150 mm, a thickness of 20 mm and a density of 0.0
It was 70 g / cc. When the oxygen concentration index of this foam plate was measured in the same manner as in Example 1, the oxygen concentration index was
Since it was 25.0%, it was confirmed that the flame retardancy was inferior.

Comparative Example 3 Except that 1 part by weight of a brominated aromatic compound having a decomposition temperature of 300 ° C. or lower (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., SR-103, decomposition temperature 260 ° C.) was used in Example 1. An attempt was made to obtain a foam plate in the same manner as in Example 1.

However, the decomposition of PET was severe during the extrusion process, and a foam plate could not be obtained.

Claims (1)

[Claims] 1. 100 parts by weight of a thermoplastic polyester resin, 0.5 to 5 parts by weight of a brominated aromatic compound having a decomposition temperature of 300 ° C. or higher, and 1 to 30% by weight of an alkyl tin laurate based on the brominated aromatic compound. A flame-retardant composition for thermoplastic polyester-based resin foams, characterized by being blended with an alkyl tin malate or an alkyl tin mercaptide.