JP3613990B2 - Thermoplastic resin composition and molded body - Google Patents

Description

【００４０】
これらの結果より以下のことが言える。
熱可塑性樹脂に無機系の紫外線吸収剤である酸化亜鉛、酸化チタン、酸化セリウム、酸化鉄および、高級脂肪酸系あるいは低分子量ポリオレフィン系ワックスを配合し、熱可塑性樹脂１００重量部に対し、無機系紫外線吸収剤を０．０１〜５重量部、顔料分散剤を顔料分散剤添加量／無機化合物添加量比Ｒで０．１≦Ｒ≦５の範囲で設定することで、紫外線吸収効果のあり、ブランクと同等の透明性を有する熱可塑性樹脂組成物およびその成形体を得ることが可能である。
【００４１】
無機系紫外線吸収剤の紫外線吸収効果は種類によって異なり、酸化亜鉛を用いた方が、ブランクの透明性を維持しながら、波長３６０ｎｍ付近の透過率も１０％以下にすることが可能である。また、比較例１から顔料分散剤を添加しないと分散性が低下し、透明性が低下することが分かる。比較例２から、酸化亜鉛添加量が多すぎると、Ｒ比を０．１≦Ｒ≦５に設定しても透明性が阻害されることが分かる。
【００４２】
比較例３から、顔料分散剤の添加量が多くなると、系全体の分子量の低下、可塑剤効果の影響で、加工性が著しく低下することが分かる。
【００４３】
【発明の効果】
本発明の熱可塑性樹脂組成物およびその成形体は、紫外線吸収効果の持続性、安全性、着色、低耐熱性等の問題を持つ有機系紫外線吸収剤の代替となり、かつ樹脂本来の透明性を損なうこともない。
また、ベースとなる材料によっては、ボトル、フィルム積層体への展開も可能であり、また、接着性を有する樹脂にも展開が可能である。[0001]
BACKGROUND OF THE INVENTION
In the present invention, 0.01 to 5.00 parts by weight of an inorganic compound having an ultraviolet absorption effect is blended with 100 parts by weight of a thermoplastic resin typified by a polyolefin resin and a polyester resin, and a pigment dispersant is added to the pigment. By making the ratio of the dispersant addition amount and the inorganic compound addition amount (R = pigment dispersant addition amount / inorganic compound addition amount) 0.1 ≦ R ≦ 5, the ultraviolet absorption effect can be obtained while having the ultraviolet absorption effect. The present invention relates to a resin composition having substantially the same transparency as a resin not containing an inorganic compound and a pigment dispersant (hereinafter referred to as a blank), and molded articles such as bottles and plates formed from the resin composition.
[0002]
[Prior art]
Conventionally, plastic molded products have been used in a wide range of fields, including packaging materials represented by containers for food, beverages, toiletries and cosmetics, as well as mechanical materials, electrical / electronic materials, optical materials, and building materials. ing. In these plastic molded products, various additives are added in order to impart functionality according to the purpose of use, and an example is an ultraviolet absorber.
[0003]
Ultraviolet rays refer to electromagnetic waves having a wavelength of 100 to 400 nm, and the energy of light in this region has energy equivalent to C, H, O binding energy (70 to 110 kcal / mol). Therefore, a plastic molded product mainly composed of C, H, and O bonds may be broken when irradiated with ultraviolet rays, which may cause deterioration of the resin, discoloration, and a decrease in mechanical strength.
On the other hand, not only plastic molded products but also contents filled in packaging materials, particularly toiletries and cosmetics, may be accompanied by discoloration, alteration, and chemical decomposition of the contents when irradiated with ultraviolet rays.
[0004]
In order to solve such problems, the above-described ultraviolet absorber is blended in the plastic molded product.
In general, organic ultraviolet absorbing materials are often used as ultraviolet absorbing materials, and representative examples thereof include phenyl salicylate, 2-hydroxy-4methoxybenzophenone, and 2 (2′-hydroxy-5methylphenyl) benzotriazole. Is mentioned. An organic ultraviolet absorbing material can be imparted with transparency and ultraviolet absorbing ability by being kneaded into a plastic molded product.
[0005]
However, the organic ultraviolet absorbing material has a problem that the molded product is colored due to its ultraviolet absorbing mechanism. In a plastic molded product, this coloring problem is accompanied by a poor appearance and should be avoided as much as possible.
Therefore, there are increasing cases of using inorganic ultraviolet absorbing materials instead of these organic ultraviolet absorbing materials. Typical examples of these include zinc oxide, titanium oxide, cerium oxide, and iron oxide.
[0006]
However, since the surface tension of these inorganic compounds is smaller than that of plastics and the interaction between inorganic compounds and plastics is inherently low, the addition of inorganic compound fine particles during plasticizing and kneading of plastics causes the following problems. .
[0007]
In general, the particle size of primary particles of inorganic compounds called ultrafine particles is on the order of several nm, and the size is equal to or smaller than the wavelength of visible light. If this inorganic compound is dispersed in the plastic in the form of primary particles, there is no problem of lowering the transparency of the plastic molded product. However, such an inorganic compound is usually added to a plastic in the form of secondary particles in which primary particles are aggregated, and is melt-kneaded.
In addition, when inorganic compound fine particles are added during plasticizing and kneading of plastic, the dispersibility of the inorganic compound particles in the plastic is lowered due to the interaction between the particles during kneading, and aggregation of primary particles or secondary particles occurs. Then, secondary particles having a dispersed particle diameter of the order of several μm to several tens of μm are generated.
When the particle size of the inorganic compound dispersed in the plastic is on the order of μm, visible light is scattered by the inorganic compound, resulting in a problem that the transparency of the plastic molded product is significantly reduced. In addition, the dispersion of the secondary agglomerated particles means that more inorganic compound is added than the addition amount that produces the effect of adding the inorganic compound, resulting in a cost increase.
[0008]
Inorganic UV absorbers are kneaded into various plastics as UV absorbers due to their excellent UV absorbing ability, but secondary agglomeration occurs by melting and kneading with plastics, resulting in plastic molding. Since the transparency of the product is lowered, it is desired to obtain a thermoplastic resin composition having transparency in which the dispersion state of the inorganic ultraviolet absorber is dispersed as finely as possible.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to consider the above-mentioned actual situation, and is a thermoplastic resin composition of a plastic molding mainly composed of a thermoplastic resin typified by a polyolefin resin and a polyester resin, and has an ultraviolet absorption effect. However, it is an object of the present invention to provide a resin composition having substantially the same transparency as that of a blank, and a molded body molded from the resin composition.
[0010]
[Means for Solving the Problems]
The present invention has been conceived to solve the above problems,
In the invention of claim 1, an inorganic compound having an ultraviolet absorbing effect and a pigment dispersant are blended in a thermoplastic resin (excluding a thermoplastic polyester resin made of an oxyacid polymer or an oxyacid copolymer) , The addition amount of the inorganic compound is 0.01 to 5.00 parts by weight with respect to 100 parts by weight of the thermoplastic resin, and the ratio of the pigment dispersant addition amount to the inorganic compound addition amount (R = pigment dispersant addition amount). / inorganic compounds added amount), a thermoplastic resin composition Ru 0.1 ≦ R ≦ 5 der, upon the plate thickness 2 mm, wavelength 700nm definitive light transmittance of 75% to 100%, the wavelength A thermoplastic resin having a light transmittance of 0 to 40% at 360 nm, a light transmittance of 0 to 10% at a wavelength of 300 nm or less, and a light transmittance of 50 to 100% at a wavelength of 400 to 700 nm. Narubutsu, it is obtained by the.
[0011]
The invention described in claim 2 is characterized in that the thermoplastic resin composition according to claim 1 contains at least one kind of zinc oxide, titanium oxide, cerium oxide, and iron oxide as an inorganic compound having an ultraviolet absorbing effect. A thermoplastic resin composition.
[0012]
The invention according to claim 3 is the thermoplastic resin composition according to claim 1 or 2, wherein the thermoplastic resin is a polyolefin resin, an olefin-vinyl compound copolymer, a polyvinyl resin, a polyester resin, a polyamide resin, or a copolymer thereof. A thermoplastic resin composition characterized by being selected from a single polymer or a mixture thereof.
[0013]
The invention according to claim 4 is the thermoplastic resin composition according to claim 1, 2 or 3, wherein a higher fatty acid or a metal salt thereof, an ester, an amide, or a low molecular weight polyolefin wax or an acid thereof is used as a pigment dispersant. A thermoplastic resin composition characterized by containing at least one modified product and copolymer.
[0015]
According to a fifth aspect, said the haze value when the thermoplastic resin composition according to any Re without gall claims 1-4, molded into plates having a thickness of 2mm is 50% or less A thermoplastic resin composition.
[0016]
Invention according to claim 6, a molded body obtained by molding the thermoplastic resin composition according to any Re without gall claims 1-5, molded body is a bottle, sheet (film), trays, shaped body characterized in that it is either Re not have a plate, in which a.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The thermoplastic resin in the present invention is a low density polyethylene resin, a medium density polyethylene resin, a high density polyethylene resin, a linear linear low density polyethylene , excluding a thermoplastic polyester resin made of an oxyacid polymer or an oxyacid copolymer. Resin, polypropylene resin, ethylene-propylene copolymer, ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer and esterified product thereof, ethylene-vinyl acetate copolymer, ethylene vinyl alcohol copolymer, polystyrene resin, It can be selected from polyester resins such as polyethylene terephthalate and polyamide resins, and these graft copolymers, block copolymers and random copolymers can also be used. Furthermore, a blend of these resins may be used.
[0018]
Examples of the inorganic compound having an ultraviolet absorption effect in the thermoplastic resin composition of the present invention include zinc oxide, titanium oxide, cerium oxide, and iron oxide. However, since iron oxide absorbs light in the visible light region, it turns slightly red, and titanium oxide and cerium oxide are inferior in ultraviolet absorption effect to zinc oxide. Zinc oxide is preferred.
In addition, the average particle size of the inorganic ultraviolet absorbing material typified by zinc oxide is preferably 10 to 100 nm in terms of blending with a thermoplastic resin and the ultraviolet absorbing effect.
The surface of the inorganic compound is surface treated with an inorganic compound such as silica or an organic material such as stearic acid as necessary for the purpose of suppressing photocatalytic activity and improving dispersibility in plastics. It doesn't matter. If necessary, these inorganic compounds may be a mixture as well as a simple substance.
[0019]
The addition amount of the inorganic compound having an ultraviolet absorbing effect to the thermoplastic resin is 0.01 to 5.00 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
If it is less than 0.01 parts by weight, the transparency when compared with the blank is comparable, but the ultraviolet absorption effect is poor.
On the other hand, when the amount is more than 5.00 parts by weight, the ultraviolet absorption effect is excellent, but the transparency when compared with the blank is remarkably lowered.
In this sense, the inorganic compound is added in an amount of 0.01 to 5.00 parts by weight with respect to 100 parts by weight of the thermoplastic resin. The amount of addition is determined by the thickness of the plate used for evaluating the light transmittance. The amount added may be adjusted accordingly.
[0020]
In order to improve the dispersibility of the inorganic compound having an ultraviolet absorption effect in the plastic, a pigment dispersant is blended.
Examples of the pigment dispersant include higher fatty acids such as stearic acid, metal salts thereof, esters and amides. In addition to such a dispersant, a low molecular weight polyolefin wax having a molecular weight of 500 to 10,000 by the viscosity method, an acid-modified product thereof, a copolymer with various monomers, or the like may be used.
In addition, even a relatively high molecular weight polymer can be used as a dispersant that decomposes when the resin and UV absorber are kneaded in a molten state, and the decomposition product exhibits the effect as a dispersant. It is.
Of course, pigment dispersants other than the above-described dispersants can be used depending on the type of the thermoplastic resin as the base. These pigment dispersants may be used alone or as a mixture.
[0021]
The addition amount of the pigment dispersant is such that the ratio of the addition amount of the pigment dispersant to the inorganic compound (R = addition amount of the pigment dispersant / inorganic compound addition amount) is 0.1 ≦ R ≦ 5.
If it is larger than 5 (the amount of the pigment dispersant is large), the average molecular weight of the resin composition itself is lowered, and the mechanical strength may be lowered or the processability may be lowered.
On the other hand, when it is less than 0.1 (when there are few pigment dispersants), the dispersion state of the inorganic compound having an ultraviolet absorbing effect is lowered, and the transparency of the resin composition may be lowered.
[0022]
The dispersion state of the inorganic ultraviolet absorber in the thermoplastic resin composition is preferably as small as the amount of the inorganic compound dispersed on the order of μm is small. If very high transparency is required, the maximum particle size is preferably 400 nm or less. However, the decrease in transparency due to the addition of an inorganic compound is due to light scattering by the inorganic compound, so depending on the thickness of the plate used for actual evaluation and the required light transmittance, It is possible to suppress the addition amount and improve transparency.
However, even in such a case, the maximum particle size of the inorganic compound dispersed in the resin composition is 5 μm or less, preferably 1 μm or less, more preferably 500 nm or less.
[0023]
The ultraviolet absorption effect of the thermoplastic resin composition of the present invention is such that when the thermoplastic resin composition of the present invention is made into a 2 mm plate, the light transmittance at a wavelength of 700 nm is 75 to 100% and the light transmittance at a wavelength of 360 nm is 0. -40%, light transmittance at a wavelength of 300 nm or less is 0-10%, and light transmittance at a wavelength of 400-700 nm is 50-100%. When the light transmittance at a wavelength of 700 nm is 75% or less, transparency is achieved.
Further, when the light transmittance at a wavelength of 360 nm is 40% or more, particularly when the light transmittance at a wavelength of 300 nm or less is 10% or more, the ultraviolet absorption effect is poor. Moreover, transparency is inferior that the light transmittance of wavelength 400-700 nm is 50% or less.
However, the evaluation method when this 2 mm thick plate is used is not a limited method, and it is preferable to maintain the ultraviolet absorption effect and transparency regardless of the thickness.
[0024]
An example of the transparency index is haze measurement. However, in the case of haze measurement, it varies greatly depending on whether the base resin is crystalline or amorphous. However, if transparency is required, the haze value is preferably 50% or less.
However, there is no problem if it has the same transparency as the blank. The evaluation method at this time also uses the above-mentioned plate having a thickness of 2 mm. However, since this method is not limited, it is preferable to maintain the ultraviolet absorption effect and transparency regardless of the thickness.
[0025]
The method for producing the thermoplastic resin composition of the present invention is carried out by melt-kneading the above-described thermoplastic resin, a predetermined amount of an inorganic ultraviolet absorbing material and a pigment dispersant by dry blending. When these compositions are melt kneaded, various kneaders such as a single screw extruder, a twin screw extruder, or a Brabender type kneader can be used.
As a method for producing a molded body comprising this thermoplastic resin composition, the molten resin kneaded using these kneaders can be cooled by water cooling or air cooling to form a film, and extruded onto a strand. After pelletizing the prepared sample, an evaluation plate may be prepared by a molding method such as injection molding or vacuum compression molding.
In addition, a masterbatch containing a high content of an inorganic ultraviolet absorber was prepared in advance using the kneader, and dry blended so that the inorganic ultraviolet absorber and the pigment dispersant were in the above-mentioned range. The evaluation plate may be prepared by a molding method such as injection molding.
[0026]
As the development of the molded body of the thermoplastic resin composition of the present invention, various forms such as a film molded body, a sheet molded body, a bottle molded body, and a tray molded body other than the above-described plate are possible. For film, use a technique such as inflation or extrusion lamination. For a sheet, use a technique such as extrusion or extrusion lamination. Then, it is possible to form a sheet molded product by a technique such as vacuum compression molding. In addition to these molded products, various molded products can be obtained.
[0027]
【Example】
Examples of the present invention are shown below, but the technical scope of the present invention is not limited to these Examples.
In addition, in the following examples and comparative examples, the addition amount of the inorganic compound and the pigment dispersant is parts by weight with respect to 100 parts by weight of the thermoplastic resin.
[0028]
<Example 1>
A low density polyethylene resin was used as the thermoplastic resin, zinc oxide having an average primary particle diameter of 20 nm was used as the inorganic compound having an ultraviolet absorbing effect, and a low molecular weight polyolefin wax was used as the pigment dispersant.
At this time, the addition amount of zinc oxide is 0.3 parts by weight with respect to 100 parts by weight of the low density polyethylene resin, and 0.3 parts by weight of the pigment dispersant (R = addition amount of the pigment dispersant / inorganic compound addition amount = 1). Set to.
This mixture of UV absorber and pigment dispersant was added to the molten low density polyethylene resin. A twin screw extruder was used for these kneading.
The molten resin extruded by the biaxial extruder was pelletized after water cooling, and a 100 mm × 100 mm plate molded body with an ultraviolet resin composition thickness of 2 mm was prepared by injection molding. The light transmittance of this plate was evaluated by a spectrophotometer, and the transparency was evaluated by comparison with a haze meter and a visually blank. These results are shown in Table 1.
[0029]
<Example 2>
Ethylene-propylene random copolymer as a thermoplastic resin, zinc oxide addition amount 0.1 parts by weight, pigment dispersant as a higher fatty acid metal salt, and addition amount 0.2 parts by weight (R = 2) Except for the above, this is the same as Example 1.
[0030]
<Example 3>
Example 1 is the same as Example 1 except that an ethylene-propylene random copolymer is used as the thermoplastic resin.
[0031]
<Example 4>
Implemented except that polyethylene terephthalate resin was used as the thermoplastic resin, the zinc oxide addition amount was 0.2 parts by weight, and the low molecular weight polyolefin wax copolymer was 0.2 parts by weight (R = 1) as the pigment dispersant. Same as Example 1.
[0032]
<Example 5>
Except for using ethylene-methyl methacrylate copolymer as a starting material, adding 1 part by weight of zinc oxide and 0.5 parts by weight of higher fatty acid ester (R = 0.5) as a pigment dispersant. Same as Example 1.
[0033]
<Example 6>
Example 2 is the same as Example 2 except that cerium oxide is used as the inorganic ultraviolet absorber and the low molecular weight polyolefin wax is used as the pigment dispersant.
[0034]
<Example 7>
Example 6 is the same as Example 6 except that iron oxide is used as the inorganic ultraviolet absorber.
[0035]
<Example 8>
Example 6 is the same as Example 6 except that the inorganic ultraviolet absorber is titanium oxide.
[0036]
<Comparative Example 1>
The same as Example 2 except that no pigment dispersant was added.
[0037]
<Comparative example 2>
The same as Example 2, except that the amount of zinc oxide added was 10 parts by weight and the pigment dispersant was a low molecular weight polyolefin wax.
[0038]
<Comparative Example 3>
It was the same as Example 2 except that the addition amount of the inorganic compound was the same and the R ratio was 20, but the melt viscosity was too low to be processed.
[0039]
[Table 1]

[0040]
From these results, the following can be said.
Inorganic UV absorber zinc oxide, titanium oxide, cerium oxide, iron oxide and higher fatty acid type or low molecular weight polyolefin type wax are blended in thermoplastic resin, and inorganic UV rays are added to 100 parts by weight of thermoplastic resin. By setting the absorbent in an amount of 0.01 to 5 parts by weight, and the pigment dispersant in the range of 0.1 ≦ R ≦ 5 with the pigment dispersant addition amount / inorganic compound addition ratio R, there is an ultraviolet absorption effect, and a blank It is possible to obtain a thermoplastic resin composition having the same transparency as that and a molded product thereof.
[0041]
The ultraviolet absorption effect of the inorganic ultraviolet absorber varies depending on the type, and the use of zinc oxide can reduce the transmittance around the wavelength of 360 nm to 10% or less while maintaining the transparency of the blank. Further, it can be seen from Comparative Example 1 that if the pigment dispersant is not added, the dispersibility is lowered and the transparency is lowered. From Comparative Example 2, it can be seen that when the amount of zinc oxide added is too large, the transparency is inhibited even when the R ratio is set to 0.1 ≦ R ≦ 5.
[0042]
From Comparative Example 3, it can be seen that when the amount of the pigment dispersant is increased, the processability is significantly lowered due to the decrease in the molecular weight of the whole system and the effect of the plasticizer.
[0043]
【The invention's effect】
The thermoplastic resin composition of the present invention and the molded product thereof are an alternative to organic ultraviolet absorbers that have problems such as durability of ultraviolet absorption effect, safety, coloring, and low heat resistance, and have the transparency inherent in the resin. There is no loss.
Further, depending on the material used as a base, it can be developed into bottles and film laminates, and can also be developed into resin having adhesiveness.

Claims (6)

An inorganic compound having a UV absorbing effect and a pigment dispersant are blended in a thermoplastic resin (excluding a thermoplastic polyester resin comprising an oxyacid polymer or an oxyacid copolymer) , and the amount of the inorganic compound added is The ratio of the pigment dispersant addition amount and the inorganic compound addition amount (R = pigment dispersant addition amount / inorganic compound addition amount) is 0.01 to 5.00 parts by weight with respect to 100 parts by weight of the thermoplastic resin. 0.1 ≦ R ≦ 5 a der Ru thermoplastic resin composition, when the plate thickness of 2 mm, light transmittance 75% to 100% of definitive wavelength 700 nm, light transmittance at a wavelength of 360nm is 0 A thermoplastic resin composition characterized by 40%, a light transmittance at a wavelength of 300 nm or less of 0 to 10%, and a light transmittance at a wavelength of 400 to 700 nm of 50 to 100% . 2. The thermoplastic resin composition according to claim 1, comprising at least one kind of zinc oxide, titanium oxide, cerium oxide, and iron oxide as an inorganic compound having an ultraviolet absorbing effect. The thermoplastic resin composition according to claim 1 or 2, wherein the thermoplastic resin is a polyolefin resin, an olefin-vinyl compound copolymer, a polyvinyl resin, a polyester resin, a polyamide resin, or a simple substance of these copolymers, or these A thermoplastic resin composition characterized by being selected from a mixture. 4. The thermoplastic resin composition according to claim 1, wherein at least a higher fatty acid or a metal salt thereof, an ester, an amide, or a low molecular weight polyolefin wax or an acid modified product or copolymer thereof is used as a pigment dispersant. A thermoplastic resin composition comprising one kind. Claim 1-4 The thermoplastic resin composition according to any Re without noise, the thermoplastic resin composition, wherein the haze value when molded into plates having a thickness of 2mm is 50% or less. A molded article obtained by molding the thermoplastic resin composition according to claim 1-5 or Re without noise, molded body is a bottle, sheet (film), trays, are either Re not have a plate A molded product characterized by that.