JPH0788438B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a resin composition, and in particular, when the resin composition is used in containers for foods, pharmaceuticals, cosmetics, etc., its contents discolor, The present invention relates to a resin composition that has less adverse effects such as alteration, sorption, and adsorption, or less interaction.

[Conventional technology]

Conventionally, various additives such as heat stabilizers have been added to resin compositions,
Antioxidants, antistatic agents, lubricants, plasticizers, colorants, and fillers are added.

Among these, as the colorant, in particular, inorganic pigments such as titanium oxide and zinc oxide, and metal-containing pigments such as various pearl pigments are used, but these pigments generally have catalytic activity, and oils and fats, drugs, Alternatively, it causes an interaction such as oxidation or reduction with a fragrance or the like to cause discoloration, odor, or the like c.

On the other hand, depending on the formulation system of the contents, it is known that the drugs and fats and oils in the contents are adsorbed and sorbed in the container and migrate, but the transferred drugs and fats and oils interact with the pigment and There are also problems such as discoloration.

For the purpose of solving such a problem, a method has been used in which the active sites of the pigment are covered with silicol oil, metal soap, silica powder or the like to block the active sites. In particular, coating with silicone oil is widely used.Coating methods using organic solvents, coating methods by mechanochemical reaction, coating methods of mixing other binding oil and silicone oil and spraying this on pigment, binding oil and silicone oil A coating method and the like in which a mixed oil and a pigment are mixed and then baked is known.

[Problems to be solved by the invention]

However, in the conventional techniques, the blocking of the catalytic activity is not always satisfactory, and the interaction with the fats and oils in the contents, the drug or the like is not completely lost.

In view of these circumstances, the present inventors have conducted extensive studies to obtain an excellent resin composition that does not interact with the contents, and as a result, the resin composition containing a pigment coated with a specific silicon compound is It was found that the resin composition satisfies the purpose, and based on this finding, the present invention was completed.

[Means for solving problems]

That is, the present invention is a resin composition characterized by containing a coated pigment obtained by coating the pigment with the compound of the formula (A).

[R ₁ SiO _3/2 ] a [R ₁ R ₂ SiO] b (A) In the formula, R ₁ represents a lower alkyl group or an aryl group, and R ₂ represents a hydrogen atom, an alkyl group or an aryl group. a is a positive integer, b is a positive integer including 0, and a and b satisfy the following relational expression 20 ≦ 100a / (a + b) ≦ 100.

The pigment used in the present invention is a pigment usually used in a resin composition, for example, titanium oxide, chromium oxide,
Iron oxide, zinc oxide, titanium yellow, cobalt blue,
Ultramarine, Mica Siena, Raw Siena, Baked Amber, Carbon black and other inorganic pigments, Titanium oxide coated mica, Colored titanium oxide coated mica, Titanium oxide coated talc and other pearl pigments, Aluminum powder, Copper powder and other metal powder pigments, diazo series , Organic pigments such as monoazo, anthraquinone and phthalocyanine, hydroxides such as magnesium hydroxide and aluminum hydroxide, carbonates such as magnesium carbonate and calcium carbonate,
Examples thereof include silicates such as sodium silicate, magnesium silicate, aluminum silicate, and potassium silicate, but are not limited thereto.

The compound for coating the surface is [R ₁ SiO _3/2 ] a [R ₁ R ₂ SiO] b (A), wherein R ₁ is a lower alkyl group or aryl group, and R ₂ is a hydrogen atom, alkyl group or aryl. Represents a group. a is a positive integer, b is a positive integer including 0, and a and b satisfy the following relational expression 20 ≦ 100a / (a + b) ≦ 100.

And has a molecular weight of preferably 200,000 or more. If the molecular weight is less than 200,000, it may be difficult to obtain a complete coating, and sufficient water repellent property may not be exhibited.

The molecular weight can be measured by gel permeation chromatography.

Further, in the present invention, the numerical values of a and b are required to be within a range satisfying 20 ≦ 100a / (a + b) ≦ 100. When the value of 100a / (a + b) is less than 20, the network structure is small and the solvent is There is a possibility that the silicon coating will fall off in the system.

R ₂ represents a lower alkyl group or an aryl group, preferably a methyl group, an ethyl group or a phenyl group, particularly preferably a methyl group.

The ratio of a and b can be calculated using the infrared absorption spectrum.

The amount of the compound of the formula (A) present in the total amount of the coated pigment of the present invention coated with the compound of the formula (A) is about 0.1 to 20.
%, Preferably 0.2 to 2.0% by weight. 0.1% by weight
If it is less than 20%, the water repellent property and the stability tend to be insufficient.
If the amount is more than weight%, the pigments are likely to aggregate with each other.

Various methods can be used for coating the pigment with the compound of the formula (A).

For example, the pigment is dispersed in a solvent of Si-H group-containing organodichlorosilane, and the surface of the pigment is hydrolyzed and cross-linked. There is a method of producing a coating of At this time, the reaction rate can be controlled by adding calcium carbonate.

Further, it can be produced by dispersing a pigment in a solvent of cyclic silicon represented by the formula (B) and then drying it, or by spraying cyclic silicon dissolved in a solvent onto the pigment and heating to dry it. You can also

(In the formula, R ₂ represents a lower alkyl group or an aryl group, R ₃ represents a hydrogen atom, an alkyl group or an aryl group. A is a positive integer, b is a positive integer including 0, and the following relational expression a + b = 3 to 100 20 ≦ 100a / (a + b) ≦ 100.) It is also possible to produce the coating of the present invention by mixing the pigment and the cyclic silicon of the formula (B) in a ball mill. is there. In this method, if the value of n in the formula (B) exceeds 100, the miscibility of the cyclic silicon and the pigment tends to deteriorate, so 100 or less is preferable.

Thus, the pigment used in the present invention can be produced by various treatment methods, but the simplest and most effective coating method is the following method utilizing the catalytic activity present on the pigment surface. is there.

That is, if one or more cyclic silicon compounds represented by formula (B) and the pigment are put in separate containers and left in a closed system, the formula (B) is naturally applied without applying any physical force. A pigment coated with the compound of A) is obtained. That is,
The volatilized cyclic silicon reaches the pigment and is adsorbed on the surface in a molecular form. The vapor pressure of the cyclic silicon in the closed system is lowered by the adsorption, and new cyclic silicon is volatilized one after another.

Conventionally, heat and a catalyst for polymerization have been considered to be indispensable for causing the polymerization of silicone oil on the surface of the pigment, but according to this method, all of them are unnecessary. The present inventors have found that the surface activity that cross-links Si—H groups in the pigment itself to generate a Si—O—Si bond allows the polymerization to proceed sufficiently.

The cyclic silicon adsorbed on the surface of the pigment is crosslinked one after another due to the surface activity of the pigment to form a network-like compound of formula (A). When the compound of formula (A) is coated on the surface of the pigment in this manner, the surface active sites on the surface of the pigment are blocked, so that adsorption, crosslinking reaction and polymerization are finally stopped, and the coating is completed.

Then, degassing removes unreacted cyclic silicon,
A pigment coated with the compound of formula (A) is obtained.

In this method, the cyclic silicon represented by the formula (B) preferably has a value of a of 3 to 8. When a is 9 or more, it becomes difficult to vaporize. Further, it is sufficient that the temperature in the closed system for accommodating both the pigment and the cyclic silicon is 100 ° C or lower. Conventionally, high temperature around 150 ° C has been required for the polymerization of cyclic silicon, but it was found that this is not necessary according to this method. This is because this method utilizes the activity of the pigment surface. By treating at a temperature of 100 ° C. or lower, deterioration of the organic pigment, which often occurs in the baking process (100 ° C. or higher) in the conventional method, does not occur. Of course, in the case of coating with a pigment that does not worry about alteration, temperature conditions exceeding 100 ° C. may be used. For example, heating at about 200 ° C. only increases the value of 100a / (a + b) and does not exceed the range of the present invention.

The pigment to be treated may be dried beforehand or may contain some water.

As described above, the above vapor phase coating treatment makes it possible to form a stable pigment simply by allowing the pigment and the cyclic silicon to stand, so that the plastic compound and the metal oxide surface-coated with the pigment can be further easily added to the silicon compound. Can be coated with.

As described above, the cross-linking of Si-H groups is generated on the surface of the pigment to form a silicon compound having a network structure to coat the surface of the pigment.
Sometimes I don't. Therefore, there is a residual Si-H group,
It may become slightly unstable under severe conditions such as the presence of alkali or acid. Alkenes and alkynes can be added to the remaining Si-H groups to generate Si-C bonds, and further stabilization can be achieved. It is also possible to change the hydrophobicity of the coated pigment by changing the carbon number of the added alkene or alkyne.

The alkene or alkyne may be a hydrocarbon having at least one unsaturated bond (double bond, triple bond) at any position, preferably at the terminal. Examples thereof include low boiling point compounds such as ethylene, propylene and butene, to octene, decene and octadecene.

As long as it has an unsaturated bond, it is added to the Si-H group at that position, so a cyclic structure such as cyclohexane, benzene, or naphthalene may be present at any other position. It is also possible to use butadiene, isoprene or the like having one or more double bonds.

The range of addition of the alkene and alkyne to the Si-H group can be carried out by contacting them in the gas phase or liquid phase for about 1 hour at 10 ° C to 300 ° C in the presence of a catalyst.

Suitable catalysts are platinum group catalysts, ruthenium, rhodium, palladium, osmium, iridium and platinum compounds, but palladium and platinum are particularly preferable. For palladium, palladium (II) chloride, ammonium tetraamminepalladium (II) chloride, palladium oxide (I
I), palladium (II) hydroxide and the like. Platinum (II) chloride, tetrachloroplatinic acid (II), platinum (IV) chloride, hexachloroplatinic acid (IV), ammonium hexachloroplatinate (IV), platinum oxide (II), platinum hydroxide (II) , Platinum dioxide (IV), platinum oxide (IV), platinum disulfide (IV), platinum sulfide (IV), hexachloroplatinic acid (I
V) Potassium acid and the like. In addition, tri-n-alkyl (n = 1 to 8) is added to these palladium and platinum compounds.
It is also possible to use the organic solvent phase after addition of methylammonium chloride and tri-n-alkylamine and ion-pair extraction with a water / organic solvent system.

At this time, the addition rate to the Si-H group can be obtained from the absorption of the Si-H group in the infrared absorption spectrum.
When the absorption of the group disappears, the addition rate becomes 100%.

The amount of the pigment coated with the compound of formula (A) in the resin composition of the present invention is 0.1 to 5 in the total amount of the resin composition.
It is 0% by weight.

The base resin is not particularly limited,
For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, olefin resin such as 4-methylpentene-1, ionomer resin, polystyrene, styrene resin such as acrylonitrile / styrene resin, polyethylene Polyester resins such as terephthalate and polycarbonate, vinyl acetate resins, and polyvinyl acetate or polyvinyl alcohol and its derivatives, polyurethane resins,
Examples include silicon resin.

When molding a container using the above resin composition, of course,
The following general molding methods can be used. That is, injection molding, extrusion molding, blow molding, inflation molding, compression molding, foam molding and the like.

〔The invention's effect〕

By using the resin composition of the present invention, it is possible to obtain a container having less interaction with the contents and no adverse effects on the contents. The coating according to the invention is strong, dense, homogeneous and transparent, so that the hue of the pigment does not change. The color can be adjusted in the same manner as the untreated case.

Moreover, since the pigment surface of the coated pigment according to the present invention becomes hydrophobic, the dispersibility is improved and the moldability is improved especially when it is added to a nonpolar resin.

〔Example〕

Hereinafter, the present invention will be described by way of examples and comparative examples will be shown together.

Example 1 Pigment treatment: 100 g of TiO ₂ (containing 93% TiO ₂ , specific gravity 4.2) powder and 20 g of tetrahydrotetramethylcyclotetrasilosan were placed in separate containers and left to stand in a room temperature closed system. After 30 hours
When TiO ₂ was taken out and the weight was measured, it was 101.4 g.
3% by weight of the thus obtained silicon-coated TiO ₂ was dispersed in a low-density polyethylene perillet mixed with usual additives such as a lubricant and a stabilizer, and a tube sleeve was extruded.

A piece of 4 × 4 cm is cut from the obtained sleeve, immersed in an O / W emulsion containing 2% of 4-t-butyl-4′-methoxybenzoylmethane and left in a constant temperature bath at 50 ° C. The color change on the surface of the piece was measured over time.

The Hitachi Color Analyzer 60 type is used to measure the color in the range of 380 to 780 nm, and the measured L, a, and b are compared with those before dipping, and Δ
E was calculated.

As a comparative example, one similar to the example except that untreated TiO ₂ was substituted was used.

The results are shown in Table 1.

As described above, in the example, the degree of discoloration of the piece is ΔE or less than half as compared with the comparative example, and there is a noticeable difference visually.

Example 2 TiO ₂ treated in the same manner as in Example 1 was mixed in high-density polyethylene at 2% by weight to obtain a white example composition, and a bottle was blow-molded from this resin composition. As a comparative example, a bottle was molded using untreated TiO ₂ .

This bottle was filled with a solubilized jelly containing 1% of vitamin E and left in a constant temperature bath at 50 ° C. for 4 weeks to determine whether the inner surface of the bottle was discolored.

The results are shown in the table below.

Example 3 The coated TiO ₂ obtained in Example 1 was placed in a 1000 ml eggplant-shaped flask, and 10 mg of tri-n-octylmethylammonium salt of chloroplatinic acid, 10 ml of 1-pentene and 300 ml of carbon tetrachloride were added thereto as a catalyst. After refluxing in a water bath for 5 hours,
The mixture was washed with chloroform and filtered, and then put in a thermostat bath at 105 ° C. and dried for 1 hour.

2% by weight of the above coated TiO ₂ was mixed to form a white polystyrene wide-mouth bottle by injection molding.

As a comparative example, it was molded using untreated TiO ₂ .

This jar was filled with an O / W emulsion containing 0.5% hinokitiol and left in a constant temperature bath at 50 ° C. for 2 weeks to determine whether the inner surface of the container was discolored.

The results are shown in the table below.

Example 4 A mixed powder of 20 g of zinc powder and 3 g of pearl pigment and a liquid of 4 g of dihydrohexamethylcyclotetrasiloxane and 4 g of pentahydropentamethylcyclopentasiloxane were put in separate containers and left at 90 ° C. in a closed container. . After 12 hours, take out the mixed powder and leave it in a 90 ° C dryer for 20 hours.
A coated powder was obtained.

A bottle was blow-molded using a resin composition obtained by mixing 1.% by weight of the above powder in high-density polyethylene.

As a comparative example, it was molded using an untreated mixed powder. This bottle was filled with a W / O cream containing 1% by weight of γ-oryzanol and left in a constant temperature bath at 60 ° C for 2 days to determine whether the inner surface of the container was discolored.

The results are shown in the table below.

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Claims (12)

[Claims] 1. A resin composition comprising a coated pigment obtained by coating a pigment with a compound of formula (A). [R ₁ SiO _3/2 ] _a [R ₁ R ₂ SiO] _b (A) (In the formula, R ₁ represents a lower alkyl group or an aryl group, and R ₂ represents a hydrogen atom, an alkyl group, or an aryl group. Is a positive integer, b is a positive integer including 0, and a and b
Satisfies the following relational expression 20 ≦ 100a / (a + b) ≦ 100. ) 2. The resin composition according to claim 1, wherein the compound of formula (A) has a molecular weight of 200,000 or more. 3. The compound of formula (A) is 0.1% of the total amount of the coated pigment.
The resin composition according to claim 1 or 2, wherein the resin composition occupies 20% (% by weight). 4. The first aspect of the present invention, wherein R ₂ is a hydrogen atom.
~ The resin composition according to any one of items 3 to 4. 5. The resin composition according to any one of claims 1 to 4, wherein R ₂ is an alkyl group having 2 to 30 carbon atoms. 6. A coating method for coating a pigment with a compound of formula (A) is a coating method in which one or more cyclic silicon compounds represented by formula (B) are brought into contact with a pigment and surface-polymerized. The resin composition according to any one of claims 1 to 5, which is characterized. (In the formula, R ₁ represents a lower alkyl group or an aryl group, R ₂ represents an alkyl group or an aryl group. A is a positive integer, b
Is a positive integer including 0 and satisfies the following relational expression: a + b = 3 to 100 20 ≦ 100a / (a + b) ≦ 100. ) 7. The resin composition according to claim 6, wherein in the compound of formula (B), a is 3 to 8 and b is 0. 8. The resin composition according to claim 6, wherein the pigment and the cyclic silicon represented by the formula (B) are contacted in a gas phase. 9. The resin composition according to claim 8, wherein the environmental temperature at the time of vapor phase contact is 100 ° C. or lower. 10. A alkene and / or alkyne is further added to the residual hydrogen atoms on the coated surface obtained by contacting and surface-polymerizing one or more cyclic silicon compounds represented by formula (B) with a pigment. The resin composition according to any one of claims 6 to 9, which is hydrosilylated. 11. The resin composition according to claim 10, wherein the alkene has a carbon number of 2 to 30. 12. The alkene double bond is in the 1 position,
The resin composition according to claim 11.