JP3252656B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition obtained by adding a polysilane and a porphyrin compound or a metal complex of a porphyrin compound to a thermoplastic resin to improve the weather resistance and ultraviolet resistance of the thermoplastic resin. .

[0002]

2. Description of the Related Art Generally, thermoplastic resins, especially resins having an ultraviolet absorbing ability, have poor weather resistance, and are significantly degraded under conditions of long-term exposure to sunlight, discoloration and transmittance. And the appearance is impaired, and the strength is reduced. For this reason, various hindered amine-based light stabilizers, benzophenone-based and benzotriazole-based light stabilizers have been used as means for preventing deterioration due to ultraviolet rays. However, these stabilizers have poor heat resistance, and have the disadvantage that they are deteriorated during the heat processing of the resin and their effects are not sufficiently exhibited.

For the purpose of resolving such drawbacks, Japanese Patent Application Laid-Open No. Hei 6-122796 has attempted to add a polysilane compound having a strong ultraviolet absorbing ability to a polystyrene resin. , It is no longer effectively contributed to the prevention of long-term deterioration of the resin.

The present invention has been made in view of the above circumstances, and has as its object to provide a thermoplastic resin composition having excellent weather resistance and ultraviolet resistance.

[0005]

Means and Action for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, it was found that the combination of a thermoplastic resin with a polysilane and a porphyrin compound or a metal complex thereof significantly increased the weather resistance and ultraviolet resistance. did.

That is, when a polysilane is simply blended into a thermoplastic resin, the ultraviolet light incident on the resin is absorbed by the resin, and then energy is transferred to the polysilane to obtain an excited state of the polysilane, or directly to the polysilane. Absorbed to obtain excited state of polysilane. Here, the polysilane in the excited state emits fluorescence having a wavelength close to the absorption wavelength and returns to the ground state, or reacts with oxygen to change to silanol or siloxane, and loses the ultraviolet absorbing ability of the polysilane. Therefore, it is difficult to expect that polysilane itself undergoes photo-oxidation and changes in quality when used alone, and functions sufficiently to suppress the deterioration of the resin. However, by adding a polysilane to the thermoplastic resin and further adding a porphyrin compound or a metal complex of the porphyrin compound, energy transfer easily occurs from the polysilane in the excited state to the porphyrin compound or the metal complex of the porphyrin compound, Through the excited state of the porphyrin compound or the metal complex of the porphyrin compound, most of the energy is released as heat or is released as fluorescence in the visible light region, so that the above-mentioned polysilane is hardly deteriorated, and therefore the resin The present inventors have found that the weather resistance is improved, and that discoloration and a decrease in transmittance can be prevented or a decrease in strength can be suppressed even after long-term use, and the present invention has been accomplished.

Hereinafter, the present invention will be described in more detail.

The thermoplastic resin composition of the present invention is obtained by blending a thermoplastic resin with a polysilane and a porphyrin compound or a metal complex thereof. That is, in general, thermoplastic resins, particularly resins having an ultraviolet absorbing ability, have poor weather resistance, are significantly deteriorated under conditions of long-term exposure to sunlight, are impaired in appearance such as discoloration and a decrease in transmittance, and have a reduced strength. Invite. In addition, it is known that a resin having no ultraviolet absorbing ability is deteriorated by photo-oxidation due to additives such as pigments. In such a case, addition of polysilane and porphyrin compound or a metal complex of porphyrin compound is also required. Works effectively and can prevent deterioration.

Here, examples of the thermoplastic resin include polyethylene, polypropylene, polymethyl methacrylate, polystyrene, polycarbonate, polyethylene terephthalate, polyoxymethylene, nylon, polyvinyl acetate, and vinyl chloride. Acts effectively on Examples of the polystyrene resin include homopolymer polystyrene, various substituted polystyrenes, styrene-maleimide copolymer, styrene-maleimide-acrylonitrile copolymer, styrene-maleimide-methyl methacrylate copolymer, and styrene-acrylonitrile copolymer. And various copolymers such as styrene-acrylonitrile-butadiene copolymer and styrene-methyl methacrylate-butadiene copolymer.

On the other hand, as the polysilane, a polysilane polymer represented by the following general formula (1) or a polysilane copolymer represented by the following general formula (2) is preferably used.

[0011]

Embedded image (However, R ¹ and R ² are each a hydrogen atom or a monovalent hydrocarbon group and may be the same or different. N is an integer of 2 or more.)

[0012]

Embedded image (However, R ¹ , R ² , R ³ , and R ⁴ each represent a hydrogen atom or 1
Is a monovalent hydrocarbon group, which may be the same or different. n is an integer of 2 or more, and m is an integer of 1 or more. )

In the above formulas (1) and (2), R ¹ ,
R ² , R ³ and R ⁴ are preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, for example, a hydrogen atom or methyl, ethyl,
Examples include alkyl groups such as propyl and hexyl, aryl groups such as phenyl and alkyl-substituted phenyl, aralkyl groups such as benzyl and phenethyl, and cycloalkyl groups such as cyclohexyl. Among such polysilanes, polymethylphenylsilane, which is easy to produce, has a high yield, and is economically advantageous, is preferably used.

The molecular weight of the polysilane is preferably 3,000 or more, more preferably 10,000 or more, in terms of weight average molecular weight. If the weight average molecular weight is less than 3,000, the polysilane becomes oily or grease-like, and the polysilane is molded. May not be possible. The upper limit is preferably up to about 2,000,000, at which polysilane can be produced.

The above-mentioned polysilane can be synthesized by an ordinary method. In the present invention, a polysilane produced by a wurtz-type condensation method using an alkali metal, which is a typical synthesis method of polysilane, is preferably used. .

The amount of polysilane is 100 thermoplastic resin.
0.01 to 10 parts by weight, especially 0.1 to 10 parts by weight
3 parts by weight is good. If the amount is less than 0.01 part by weight, the effect of ultraviolet absorption is poor, and does not contribute to the suppression of resin deterioration. 10
When the amount is more than the weight part, the effect of suppressing deterioration is not improved, which not only causes an increase in cost but also causes a case where various physical characteristics of the resin are changed.

Next, as the porphyrin compound or its metal complex, natural porphyrin can be used, but synthetic porphyrin is preferable from the viewpoint of thermal stability and the like, and tetraphenyl porphyrin represented by the following formula (3) and the following formula (4) Octaethylporphyrin represented by or a metal complex thereof is preferably employed.

[0018]

Embedded image (However, M is a metal atom, and n is 0 or 1.)

In this case, various metals can be used as the central metal M in the above formulas (3) and (4). Specifically, Ti, V, Mn, Fe, Co, Zn, Nb, Mo , R
h, Cu, etc. are typical.

The amount of the porphyrin compound or its metal complex is 0.01 to 5 parts by weight based on 100 parts by weight of the polysilane.
It is preferred that the amount be 0.01 parts by weight, particularly 0.01 to 3 parts by weight. If the amount is less than 0.01 part by weight, there is no deterioration suppressing effect,
Further, even if it is added in an amount of more than 5 parts by weight, the effect does not increase and it is uneconomical.

The method of blending the polysilane and the porphyrin compound or its metal complex (hereinafter simply referred to as porphyrin) with the thermoplastic resin can be selected as appropriate. Therefore, after dissolving and mixing using a good solvent common to all three, shaping while evaporating the solvent, and forming and evaporating the residual solvent after concentrating to a viscous liquid, etc. Is adopted. Also, after dissolving and mixing using a common solvent for both polysilane and porphyrin,
A method of spraying on a resin pellet or the like, a method of precipitating with a poor solvent of both to obtain a powder, and mixing the powder with the resin pellet are employed. Examples of good solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, and ether solvents such as tetrahydrofuran and butyl ether. Alcohols are preferably used as the poor solvent. The resin to which polysilane and porphyrin are added can be appropriately processed into a desired molded product by various general molding methods of thermoplastic resin such as roll, extrusion, injection molding and the like.

[0022]

According to the present invention, by adding polysilane and a porphyrin compound or a metal complex of a porphyrin compound to a thermoplastic resin, the weather resistance and ultraviolet resistance of the thermoplastic resin can be improved, and the thermoplastic resin can be used for a long time. This also prevents discoloration and a decrease in transmittance, and can suppress a decrease in strength.

[0023]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Reference Example 1 A 300 ml four-necked round bottom separable flask was charged with a stirrer, a Dimroth condenser, a thermometer,
The vessel was equipped with a 50 ml dropping funnel, and allowed to stand overnight while passing dry nitrogen through the vessel. 5.06 g of metallic sodium in the vessel
(0.22 mol) and 140 ml of dried dodecane were charged and heated to 190 ° C. on an oil bath. On the other hand, 19.1 g of phenylmethyldichlorosilane (0.
1 mol), and the mixture was gradually added dropwise over 15 minutes while maintaining the inside of the flask at 190 ° C. After the completion of the dropwise addition, the temperature was kept at 190 ° C. for further 45 minutes to cool and terminate the reaction.
Then, the mixture was filtered through a glass filter under a nitrogen stream to obtain 1
After washing with 0 ml of dodecane, a filter cake and a filtrate were obtained. The filter cake was further thoroughly washed with n-octane, further washed with methanol and then with water, and dried to obtain 8.6 g of a crude product (71%). As a result of GPC measurement of the crude product of polysilane, the weight average molecular weight was 138,000. This crude product was dissolved in 260 ml of toluene, washed three times with a separating funnel, dried over magnesium sulfate, and filtered. Then, 500 ml of acetone was gradually added under stirring with a magnetic stirrer to perform reprecipitation,
By filtration and drying, 5.2 g of purified polysilane was obtained (yield 43%, weight average molecular weight 198,000).

[Examples 1 to 5, Comparative Examples 1 and 2] 5 of commercially available polystyrene powder (weight average molecular weight: 280,000)
The polysilane obtained in Reference Example 1 was added to 10 mg
mg and 0.2 mg of a commercially available tetraphenylporphyrin-zinc complex were added, dissolved in toluene, and formed into a 40 μm film. When the strength and elongation were measured by a tensile tester, they were 402 kg / cm ² , 2.
2%. After exposing it outdoors for 6 months, the elongation of strength was measured in the same manner. As a result, the elongation was 385 kg / cm ² and 2.1%, respectively.

Further, a film having a thickness of 40 μm was obtained in the same manner as described above according to the formulation shown in Table 1, and the strength and elongation after being exposed outdoors for 6 months were measured. Table 1 shows the results.

[0027]

[Table 1] From the above results, it was found that the effect of adding polysilane and porphyrin-zinc complex was remarkable.

Continuation of the front page (56) References JP-A-6-122796 (JP, A) JP-A-3-144656 (JP, A) JP-A 1-135887 (JP, A)

Claims (1)

(57) [Claims] 1. A thermoplastic resin composition comprising a thermoplastic resin and a polysilane and a porphyrin compound or a metal complex thereof, wherein the amount of the polysilane is from 0.01 to 100 parts by weight of the thermoplastic resin. A thermoplastic resin composition comprising 10 parts by weight, and the compounding amount of the porphyrin compound or its metal complex is 0.01 to 5 parts by weight based on 100 parts by weight of the polysilane.