JPH082999B2 - Polyolefin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyolefin composition having excellent weather resistance or ultraviolet resistance.

As is well known, the polyolefin resin and the polyolefin rubber are used for a wide range of applications, and are exposed to direct sunlight outdoors, or used at high temperatures. Often used under various conditions.

In this case, polyolefins are generally sensitive to UV light,
For example, polyethylene is 300 nm, polypropylene is 370 nm,
Polystyrene is easily degraded at a wavelength of 318 nm.
For this reason, it has been practiced to add an ultraviolet absorber to polyolefin.

Heretofore, p-aminobenzoic acid-based, benzophenone-based, benzotriazole-based, salicylate-based, substituted acrylonitrile-based compounds and the like have been known as additives to be added to polyolefins for such a purpose. Additives such as titanium are also widely used.

However, most of these compounds are solid at room temperature, have poor compatibility with polyolefins, and the addition amount is limited, so that there is a problem that the ultraviolet absorption performance cannot be sufficiently exhibited. Further, blooming occurs even if the amount of addition is increased, and on the contrary, there is a problem that the effect is remarkably reduced. Furthermore, when used for packaging materials such as foods and pharmaceuticals, it must be non-toxic from the viewpoint of safety and hygiene.
When used as a transparent resin, transparency is required, and in addition, thermal stability, chemical stability, stability against diffusion and migration, etc. are also required, but conventional UV absorbers have these performances. It is difficult to be fully satisfied.

On the other hand, conventionally, it is known that organopolysilanes having a Si-Si bond exhibit ultraviolet absorption, and especially for dimethylpolysilanes, the absorption wavelength range may shift to the long wavelength side as the silicon chain becomes longer. Although it has been observed, conventionally well-known dimethylpolysilanes have an ultraviolet absorption region of a wavelength shorter than 250 nm, and in general, the absorption of 300 nm or more necessary for preventing ultraviolet deterioration of polyolefin is insufficient.

The present invention has been made in view of the above circumstances, and has an excellent ultraviolet absorbing ability adapted to the ultraviolet deterioration region of polyolefin-based resins and rubbers, good compatibility with polyolefin-based resins and rubbers, thermal and chemical It is an object of the present invention to provide a polyolefin composition having excellent weather resistance, which is blended with an ultraviolet absorber having good thermal stability.

Means and Actions for Solving the Problems As a result of examining the ultraviolet absorbing effect of various organopolysilanes in order to achieve the above-mentioned object, the present inventor,
In the molecule, the following formula (1) R ¹ R ² Si _n (1) (wherein, R ¹ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R ² is a substituted or unsubstituted carbon) A group selected from an alkyl group, a cycloalkyl group and an aryl group of 3 or more, n is an integer of 2 to 50), and a polysilane structural unit represented by the following formula (2): (Wherein R ³ is a group selected from a hydrogen atom, a hydroxyl group, a substituted or unsubstituted monovalent hydrocarbon group and OR ⁴ (R ⁴ substituted or unsubstituted monovalent hydrocarbon group), and a is 0 < a is a positive number of 4), and an organic silicon compound containing a structural unit represented by
It has an excellent absorption effect on ultraviolet rays of 300 to 400 nm, which is the wavelength of UV deterioration of polyolefin, and it can change the absorption wavelength range by changing the polymerization degree of the polysilane structure and the type of organic substituents. Is chemically stable, and has good compatibility with polyolefin due to the introduction of the structural unit of the formula (2). When the above organosilicon compound is blended with a polyolefin resin or rubber as an ultraviolet absorber, the polyolefin composition It was found that the product maintains excellent UV resistance for a long period of time and exhibits good weather resistance,
The present invention has been completed.

Therefore, the present invention provides a polyolefin composition obtained by blending a polyolefin-based resin or a polyolefin-based rubber with an ultraviolet absorber composed of an organosilicon compound containing the structural units of the above formulas (1) and (2).

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

The ultraviolet absorber according to the present invention has the following formula (1) R ¹ R ² Si _n (1) in the molecule (wherein R ¹ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, R ² is a group selected from a substituted or unsubstituted alkyl group having 3 or more carbon atoms, a cycloalkyl group and an aryl group, and n is an integer of 2 to 50.), and a polysilane structural unit represented by the following formula: 2) (Wherein R ³ is a group selected from a hydrogen atom, a hydroxyl group, a substituted or unsubstituted monovalent hydrocarbon group and OR ⁴ (R ⁴ substituted or unsubstituted monovalent hydrocarbon group), and a is 0 < a is a positive number of 4) and a structural unit represented by:

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

The ultraviolet absorber according to the present invention is the above (A) or (B).
Of the organosilicon compound of.

Here, R ¹ is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group,
Examples thereof include a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Among them, an alkyl group having 3 to 10 carbon atoms is preferable, and R ² is a substituted or unsubstituted C 3 or more carbon atom. An alkyl group, a cycloalkyl group or an aryl group is preferable, and a phenyl group is particularly preferable.
Further, R ¹ and R ² may be a group in which a part or all of hydrogen atoms bonded to the carbon atoms are substituted with a halogen atom or the like, for example, trifluoropropyl group. Furthermore, 2 to 50,
It is more preferably 5 to 50, further preferably 10 to 20.

Further, R ³ is a hydrogen atom, a hydroxyl group, a substituted or unsubstituted monovalent monovalent hydrogen group, or OR ⁴ (R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group), as these monovalent hydrocarbon groups Include an alkyl group, an alkenyl group, an aryl group, and the like having 1 to 10 carbon atoms, and a part or all of the hydrogen atoms bonded to these carbon atoms may be substituted with a halogen atom or the like. .

Examples of the above-mentioned organosilicon compound include those of the following formula (ii) obtained by siloxane modification of the silane of the following formula (i).

(I) XR ¹ R ² Si _n X (R ¹ , R ² and n have the same meanings as described above, and X represents a hydrogen atom or a hydroxyl group.) (In the formula, R ¹ , R ² , and n have the same meanings as described above, R ^{5 to} R ¹³ are each an alkyl group, an alkenyl group, or an aryl group having 1 to 3 carbon atoms, A is an alkylene group, and Y is hydrogen. Atoms, hydroxyl groups, alkyl groups having 1 to 3 carbon atoms, alkenyl groups or aryl groups, and b and c each represent a number of 1 or more.) Specific examples of the compound of the formula (ii) include a vinyl functional polysilane having a terminal vinyl group. CH ₂ = CHR ¹ R ² Si _n CH = CH ₂ and SiH-containing polysiloxane The following compound obtained by reacting with And the like.

(However, in the formulas (iii) and (iv), R ¹ , R ² , n and A, Y
Represents the same meaning as described above, R ^{14 to} R ²⁰ are each an alkyl group, an alkenyl group or an aryl group having 1 to 3 carbon atoms, d
Indicates a number of 1 or more. ) Specific examples of these compounds of the formulas (iii) and (iv) include terminal vinyl functional polysilane CH ₂ ═CHR ¹ R ² Si _n CH
= CH ₂ and polysiloxane containing SiH at one end The following compound obtained by reacting with as well as And the like.

Also, terminal SiH-containing polysilane HR ¹ R ² Si _n H and terminal vinyl-functional polysiloxane Obtained by reacting with Can also be mentioned such as _{^{(v) (R 22 O 3}} -e R e 21 Si-AR 1 R 2 Si n A-SiRR
_e ²¹ (OR ²² ) _3-e (wherein R ¹ , R ² , n and A have the same meanings as described above, R ²¹
Is an alkyl group having 1 to 3 carbon atoms, an alkenyl group or an aryl group, R ²² is a lower alkyl group or a trialkylsilyl group, and e is 0 or 1. ) Specific examples of the compound of the formula (v) include terminal vinyl polysilane CH ₂ ═CHR ¹ R ² Si _n CH ═CH ₂ and SiH-containing alkoxysilane (for example, HSi (OCH ₃ ) ₃ , HCH ₃ Si (OC ₂ H ₅ ) ₂ )
The following compounds which are reaction products with And so on.

Further, terminal SiH polysilane HR ¹ R ² Si _n H and vinylalkoxysilane etc. (eg CH ₂ ═CHSi (OCH ₃ ) ₃ , CH ₂ ═CH
The following compound (CH ₃ O) ₃ SiCH ₂ CH ₂ R ¹ R ² Si _n CH ₂ CH ₂ Si (OCH ₃ ) ₃ obtained by reacting with Si (OSi (CH ₃ ) ₃ ) ₃ ) In addition, in the above formulas (ii) to (v), the alkylene group of A is preferably one having 1 to 3 carbon atoms, particularly ethylene group, and b is 1 to 10, particularly 1 to 5, Each of c and d is preferably 1 to 20, particularly preferably 2 to 20.

In the above-mentioned compounds, the part which gives the ultraviolet absorbing effect aimed at by the present invention is the organopolysilane part of the formula (1), and the structural unit part of the formula (2) in these compounds does not affect the ultraviolet absorbing effect. These give solvent solubility and improve compatibility with polyolefin. For example, the organopolysilane of the formula (i) has good solubility in an aromatic solvent, but its solubility in an aliphatic hydrocarbon is low, and its solubility increases as the silicon chain in the formula (i) becomes longer. Alkylphenyl polysilanes are difficult to dissolve in aliphatic hydrocarbons, and dialkyl polysilanes are difficult to dissolve in tetrahydrofuran and the like when the silicon chain is long. Therefore, in the organopolysilane of the formula (i), when the number of n is increased and the silicon chain is lengthened, the ultraviolet absorption maximum shifts to the long wavelength side, and at the same time, the absorption maximum increases and the ultraviolet absorption ability improves. In addition, the compatibility with the solvent decreases, but by introducing the structural unit of the formula (2) into it,
For example, by modifying the siloxane and adding a siloxane chain, the solubility in the solvent is improved and the compatibility with the polyolefin is improved. As a result, by changing the degree of polymerization of polysilane and the type of organic group of polysilane to give a desired ultraviolet absorption region from the far ultraviolet region to the near ultraviolet region, compatibility can be changed by introducing various polysilanes. Therefore, as the organosilicon compound according to the present invention, it is possible to select an optimum one having an ultraviolet absorption region adapted to the ultraviolet region that deteriorates the polyolefin and having compatibility depending on the type of the polyolefin.

In addition, the organosilicon compound according to the present invention has few hygienic restrictions when incorporated into a polyolefin due to its structure.

A known method is adopted for synthesizing the organosilicon compound having the structural units represented by the above formulas (1) and (2).

For example, polysilanes can be obtained by reacting an organochlorosilane and an alkali metal (M) in a solvent such as toluene, xylene or tetrahydrofuran.

R ¹ R ² SiCl ₂ + M → R ¹ R ² Si _n ＋ MCl R′R ″ RSiCl / R ¹ R ² SiCl ₂ + M → R′R ″ RSi (R ¹ R ² Si) _l SiR′R ″ R + MCl In this case, A chain polymer or a three-dimensional polymer can be obtained by selecting the number of chlorines, and monochlorosilane acts as a chain length terminating agent to control the degree of polymerization.

The introduction of the alkenyl group can be carried out by using vinylchlorosilanes, for example, as follows.

(CH ₂ = CH) R ¹ R ² SiCl / R ¹ R ² SiCl ₂ + M → CH ₂ = CH (R ¹ R ² Si) _n CH = CH ₂ Furthermore, the introduction of SiH group can be performed by, for example, HR ¹ R ² SiCl. _{^{/ R 1 R 2 · SiCl 2}} + M → HR 1 may be employed the reaction of R ² · Si _n H.

When the polysilanes thus obtained are modified to obtain the compounds of the above formulas (ii) to (v), known methods can be used. As described above, Si-CH = CH ₂ and Si-
An addition reaction with H is preferably used, and further, for example, Cl
Co-hydrolysis method of R ¹ R ² Si _n Cl and chlorosilane, ClR ¹ R ² S
i _n such as Na by condensation reaction between Cl and ClR'R "SiOSiR'R" Cl can be prepared by utilizing.

The ultraviolet absorber of the present invention is composed of one or more of the above-mentioned organosilicon compounds. In this case, when the organopolysilane having the structural unit of the above formula (1) is used alone, it is as described above. Generally, it is well soluble in aromatic solvents, but alkylphenyl polysilanes tend to be poorly soluble in aliphatic solvents, and dialkyl polysilanes tend to be less soluble in tetrahydrofuran as the degree of polymerization increases. Therefore, when compounding with a polyolefin-based resin or rubber, the compounds of the formulas (ii) to (v) are appropriately selected from the viewpoint of compatibility depending on the type of the polyolefin-based resin or rubber in consideration of the compoundability. It is preferable to use.

Here, examples of polyolefin resins and polyolefin rubbers containing these organosilicon compounds include homopolymers of olefins and copolymers of two or more kinds of olefins, and specifically, polyethylene, polypropylene, ethylene-propylene copolymers. Resins and rubbers such as ethylene, propylene diene terpolymer, ethylene / vinyl acetate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl methacrylate copolymer, isobutylene / isoprene copolymer, polystyrene and polyvinyl chloride are exemplified. In this case, the composition of the present invention may be used by blending two or more of these polyolefin resins and rubbers.

The amount of the above-mentioned organosilicon compound is usually 0.1 to 10 parts by weight, and particularly preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the polyolefin-based resin or rubber, although it varies depending on the type of polyolefin and the purpose of use. . If the amount is less than 0.1 parts by weight, the effect of the compound may not be sufficiently exhibited, and if the amount is more than 10 parts by weight, the ultraviolet resistance may not be improved and it may be uneconomical.

In addition, the polyolefin composition of the present invention includes a plasticizer, a stabilizer, a filler, a reinforcing agent, an antioxidant, a foaming agent, a flame retardant, an antistatic agent, a lubricant, and a colorant, which are usually blended with the polyolefin composition. The polymer-based modifier may be blended within the usual range without any problem.

Effects of the Invention The polyolefin composition of the present invention has excellent ultraviolet absorption ability in the ultraviolet wavelength range of 300 to 400 nm that deteriorates the polyolefin resin and rubber, and also has thermal and chemical stability, and also has a polyolefin resin. By blending the above-mentioned organosilicon compound having high compatibility with or rubber, it has no bloom and has excellent weather resistance.

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

Reference Example 1 The UV absorption maximum wavelength (λmax) and the absorption coefficient (ε) of organopolysilanes having various polymerization degrees and organic groups having both ends of ≡SiH shown in Table 1 are U-3400 spectrophotometer manufactured by Hitachi. It was measured using a meter (1 cm standard cell). The results are shown in Table 1.

[Reference Example 2] Synthesis Example 1 400 g of toluene and 23 g of sodium metal pieces were placed in a four-necked flask equipped with a mechanical stirrer, a thermometer, a condenser, a dropping funnel and a nitrogen introducing tube, and heated in nitrogen. The sodium was melted. Then
90 g of methylphenyldichlorosilane with vigorous stirring
(0.47 mol) was added dropwise over 1 hour and then refluxed for 3 hours. After cooling, the solid was separated, the solvent was removed from the liquid, and the residue was washed with a tetrahydrofuran / isopropanol solution to give a molecular weight n11,000 (GPC) solid product [HCH ₃ C ₆ H ₅ Si ₉₇ H]. 29 g (yield 52%) was obtained.

Synthesis Example 2 Toluene was prepared in the same manner as in Synthesis Example 1 except that toluene was used.
The reaction was carried out using 400 g, 23 g of sodium metal pieces, 80 g (0.42 mol) of methylphenyldichlorosilane and 14.6 g (0.08 mol) of methylphenylvinylchlorosilane, and after the reaction was cooled, the solid was separated. Remove the solvent from the liquid,
Then washed with petroleum ether and acetone to obtain a molecular weight of n185.
0 semisolid product (GPC) _{[CH 2 = CH (CH 3 C} 6 H 5 Si) 15 CH =
CH ₂ ] 23 g (yield 38%) was obtained.

Next, 10 g of the organopolysilane obtained above was dissolved in 120 g of toluene, about 0.5 ml of chloroplatinic acid-butanol catalyst (2% by weight of platinum) was added, and the mixture was heated to 60 ° C. and H (C
H ₃ ) ₂ Si (OSi (CH ₃ ) ₂ ) ₁₈ OSi (CH ₃ ) ₃ 8.0 g was added dropwise to cause a reaction, and a viscous product was obtained. 15 g (yield 83%) was obtained.

Next, the compounds of Synthesis Examples 1 and 2 above were mixed at a concentration of 3 mg / 100 ml and 6 m.
It was dissolved in hexane at g / 100 ml and the ultraviolet transmittance was measured using a Hitachi U-3400 spectrophotometer (1 cm standard cell). The results are shown in FIG. 1 (synthesis example 1) and FIG. 2 (synthesis example 2), respectively.

For comparison, a commercially available ultraviolet absorber, phenyl salicylate (V Sorb 201) Of 25mg / 100ml isopropyl alcohol solution, 2,2'-dihydroxy-4-methoxybenzophenone (Thiasorb UV24) in 5mg / 100ml toluene solution, and benzotriazole derivative (Tinuvin320) in 5mg / 100ml chloroform solution were measured for UV transmittance. The results are shown in FIG.
It is shown in FIG.

[Example 1] A polyolefin composition prepared by mixing 1.5 parts of a commercially available polyethylene resin with 1.5 parts of the organosilicon compound synthesized in Synthesis Example 2 was formed into a sheet shape, respectively, and exposed to the outdoors for 6 months. Was measured for tensile strength and elongation.
The results are shown in Table 2.

The tensile strength of the composition containing no ultraviolet absorber was 180 kg / cm ² when measured after 2 months, and there was a phenomenon in which the tensile strength temporarily increased due to crosslinking by ultraviolet rays and then decreased. It was also confirmed that the elongation was also greatly reduced and that the physical properties were significantly reduced by ultraviolet rays.

On the other hand, in the composition containing the organosilicon compound according to the present invention, almost no increase in tensile strength due to crosslinking was observed, and the initial value was maintained.

[Example 2] SEP1721U (manufactured by Shin-Etsu Chemical Co., Ltd.), which is a hybrid rubber of ethylene propylene rubber (EPDM) and silicone 10
To 0 parts, 3.0 parts of the organosilicon compound obtained in Synthesis Example 2 was added, and 3 parts of dicumyl peroxide (DCP40) was added and vulcanized to prepare a sheet having a thickness of 2 mm.

Then, according to ASTM-G53, the above sheet was exposed to ultraviolet rays in an atmosphere of 70 ° C. using UVCON (manufactured by Atlas),
Table 3 shows the results of observing the state of crack generation at 0% elongation and evaluating them in the following three stages.

Evaluation of crack occurrence ○: No crack occurs at 100% elongation △: Slight cracks occur in a hair shape at 100% elongation ×: Crack occurs at 100% elongation From the results shown in Table 3, it was confirmed that the composition of the present invention has excellent weather resistance.

[Brief description of drawings]

1 and 2 are the ultraviolet absorption spectrum of the ultraviolet absorbent of the reference example, FIG. 3 is the ultraviolet absorption spectrum of phenyl salicylate, and FIG. 4 is the ultraviolet absorption spectrum of 2,2′-dihydroxy-4-methoxybenzophenone. , FIG. 5 is an ultraviolet absorption spectrum of a benzotriazole derivative.

Claims (1)

[Claims] 1. A polyolefin-based resin or polyolefin-based rubber having the following formula (1) R ¹ R ² Si _n (1) in the molecule (wherein R ¹ is a substituted or unsubstituted carbon number 1 to 1). An alkyl group of 10, R ² is a group selected from a substituted or unsubstituted alkyl group having 3 or more carbon atoms, a cycloalkyl group and an aryl group, and n is an integer of 2 to 50). And the following formula (2) (Wherein R ³ is a group selected from a hydrogen atom, a hydroxyl group, a substituted or unsubstituted monovalent hydrocarbon group and OR ⁴ (R ⁴ substituted or unsubstituted monovalent hydrocarbon group), and a is 0 < a is a positive number of 4). A polyolefin composition comprising an organic silicon compound containing a structural unit represented by: