JPH0528729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a colored olefin resin composition from which a colored olefin resin molded article having excellent weather resistance can be obtained and which has excellent moldability.

(Prior Art) Olefin resins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymers are widely used in various molded products including various films and textile products.

Olefin resins are inherently susceptible to embrittlement and powdering due to deterioration due to ultraviolet rays and heat, and deterioration is particularly rapid when placed outdoors. Therefore, light stabilizers are usually added. For example, Tokuko Sho 61-11255
In the publication, bis(phenyl-
(2-Hydroxy-4-octyloxyphenylketoxime) nickel is disclosed. Since such a light stabilizer is added, deterioration of the resin is suppressed. However, pigments added to olefin resins for coloring cause resin deterioration (light deterioration, heat deterioration).
may be promoted. Previous research has revealed that there are pigments that suppress or do not promote the deterioration of olefin resins, and pigments that promote the deterioration of the resins. For example, among inorganic pigments,
Lead chromate pigments such as yellow lead; cadmium pigments such as cadmium yellow and cadmium orange (all called heavy metal pigments) suppress or do not substantially accelerate the deterioration of olefin resins. However, since these are harmful to living things, there is a risk of environmental pollution if they are used. On the other hand, titanium pigments such as titanium white and titanium yellow; synthetic iron oxide pigments commonly known as red iron oxide and yellow iron oxide are harmless or have low toxicity to living things, but they degrade the olefin resin. promote. Deterioration of the resin can be suppressed by selecting a pigment, but as for green, white, and yellow pigments, a harmless pigment that does not promote resin deterioration has not yet been developed.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional drawbacks, and its purpose is to provide a pigment that has excellent weather resistance and low toxicity to living organisms. An object of the present invention is to provide a colored olefin resin composition from which an olefin resin molded article colored in a desired color can be prepared. Another object of the present invention is to provide a colored olefin resin composition with excellent moldability.

(Means and Effects for Solving the Problems) The present invention aims at reducing the concentration of free transition metal ions, since deterioration of olefin resins is accelerated due to free metal ions (particularly transition metal ions) originating from pigments. This was completed based on the inventor's knowledge that resin deterioration can be suppressed by reducing as much as possible.

Therefore, the colored olefin resin composition of the present invention comprises: an olefin resin; a surface-treated inorganic pigment whose surface is coated with silicon oxide and/or silicon hydroxide; and at least two types of pigments having different softening points. A light stabilizer; thereby achieving the above object.

The olefin resins contained in the composition of the present invention include common olefin resins such as polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer. They are selected depending on the type of body and purpose of use.

Pigments used for coloring are mainly inorganic pigments, and any known pigments can be used. For example, titanium oxide pigments such as titanium white and titanium yellow; iron oxide pigments containing synthetic iron oxides commonly known as red iron oxide and yellow iron oxide;
Chromium oxide pigment; examples include spinel-type fired pigments such as spinel green.

Since such inorganic pigments are themselves metal compounds, in the present invention, their surfaces are coated with silicon oxide and/or silicon hydroxide and used as surface-treated inorganic pigments. The surface-treated inorganic pigment can be obtained, for example, by a conventional method in which the above-mentioned ordinary inorganic pigment is finely dispersed in water, and an aqueous solution of sodium silicate, potassium silicate, etc. and a dilute sulfuric acid aqueous solution are added dropwise thereto and stirred. In the produced surface-treated inorganic pigment, the surfaces of the inorganic pigment particles are almost uniformly coated with silicon oxide and/or silicon hydroxide. The amount of silicon oxide and/or silicon hydroxide is 10% per 100 parts by weight of the inorganic pigment.
It is contained in a proportion of ~100 parts by weight, preferably 25 to 60 parts by weight. If the amount of silicon oxide and/or silicon hydroxide is too small, the resin deterioration prevention effect will be insufficient, and if it is in excess, the pigment surface will be coated thickly, so it is necessary to ensure the desired degree of coloring. requires large amounts of surface-treated inorganic pigments. Moreover, no resin deterioration preventing effect is observed in proportion to the amount of silicon oxide and/or silicon hydroxide.
The surface-treated inorganic pigment produced in the reaction solution is thoroughly washed with water and dried before use. The surface-treated inorganic pigment is usually contained in the composition in an amount of 0.1 to 5% by weight.

In addition to the above-mentioned surface-treated inorganic pigments, organic pigments may also be contained. Known compounds can also be used as organic pigments. For example, monoazo pigments; disazo pigments; condensed azo pigments such as polyazo yellow; anthraquinone pigments; perinone/perylene pigments; indico/thioindico pigments;
There are isoindolinone pigments such as isoindolinone yellow; phthalocyanine pigments such as phthalocyanine green and phthalocyanine blue; quinacridone pigments such as quinacridone; dioxazine pigments; and carbon black.

The organic pigments mentioned above usually contain metal oxides of metals such as copper, iron, cobalt, manganese, and titanium, which are derived from the catalysts and unreacted raw materials used when synthesizing them, or are mixed in from manufacturing equipment. Existed in trace amounts (usually over 200 ppm). in this way
The presence of 200 ppm or more of transition metal ions, especially copper ions, accelerates the deterioration of the resin, as in the case of the above-mentioned inorganic pigments. Therefore, in the present invention, organic pigments with low metal content are used. In this way, as an organic pigment, the free transition metal ion concentration in the composition is relative to the weight of the olefin resin.
Those with a concentration of 1 ppm or less are selected. usually,
The free transition metal ion concentration in the organic pigment used is
Organic pigments are utilized that are less than 100 ppm, preferably less than 50 ppm. Such an organic pigment can be obtained, for example, by thoroughly washing a commercially available organic pigment or a synthetically obtained organic pigment in a dilute aqueous acid solution to remove transition metal ions. The organic pigment is usually contained in the composition in a proportion of 2% by weight or less, although it varies depending on the type and the desired degree of coloring.

Next, the light stabilizer contained in the composition of the present invention will be explained. Generally, the light stabilizer contained in the olefin resin composition has a softening point of 50 to 150°C.
There are many compounds. These gradually percolate onto the surface of a molded article obtained by molding an olefin resin composition (referred to as a blooming phenomenon), where they exhibit a photostabilizing effect. Such light stabilizers tend to separate from the resin and precipitate during kneading and molding using the composition, as well as during post-molding processing (for example, stretching). By the way, as mentioned above, in the present invention, a surface-treated inorganic pigment is used in order to prevent deterioration of the olefin resin. Since the pigment surface of this surface-treated inorganic pigment is coated with silicon oxide and/or silicon hydroxide, in order to obtain the same degree of coloring as when using ordinary inorganic pigments,
It is necessary to add about 15-30% excess. Since a relatively large amount of the surface-treated inorganic pigment is added in this way, the surface-treated inorganic pigment is precipitated on the resin surface together with the light stabilizer, the dispersant in the composition, etc. during the molding process and stretching process. . Inorganic pigments are solid during molding due to their high melting point, and when mixed with the above-mentioned light stabilizer (which has been softened by heating), they become mud-like and precipitate.
Adheres to molds, stretching rolls, heat setting plates, etc.
The attached precipitates are treated with light stabilizers that have a high softening point (120~
If the temperature is 150°C, the material will cool and solidify, and precipitates will adhere to it, resulting in fiber breakage and lower processing efficiency.
In some cases, molding or processing becomes impossible.

In order to solve such molding problems, at least two types of light stabilizers are blended into the composition in the present invention. Among the plurality of light stabilizers, the difference in softening point between the light stabilizer with the highest softening point and the stabilizer with the lowest softening point is 10° C. or more. When light stabilizers having different softening points are used in this manner, the light stabilizer having a lower softening point becomes liquid due to heating during molding and precipitates first. Since the liquid light stabilizer has the function of a lubricant, even if the pigment and the like are precipitated from the resin, it does not adhere to the molding die or the molding roll.
Thus, it can be said that the composition has a self-cleaning effect during molding or subsequent processing. Therefore, it has excellent moldability and does not cause any trouble even when operated for a long period of time.

Light stabilizers that can be used in the present invention are known compounds, such as dimethyl succinate-1
-(2-hydroxyethyl)-4-hydroxy-
2,2,6,6-tetramethylpiperidine polycondensate (softening point: 55-70°C); bis(2,2,6,6
-tetramethyl-4-piperidyl) sebacate (softening point: 85°C); N,N'-bis(2,2,6,
6-tetramethyl-4-piperidyl)hexamethylenediamine polymer (softening point: 93-98°C); poly[(6-(1,1,3,3-tetramethylbutyl)
imino-1,3,5-triazine-2,4-piperidyl][2,2,6,6-tetramethyl-4-
piperidyl)imino]hexamethylene [(2,2,
6,6-tetramethyl-4-piperidyl)imino] (softening point: 100°C to 135°C). Among these light stabilizers, two or more compounds such that the difference between the softening point of the light stabilizer with the highest softening point and the softening point of the light stabilizer with the lowest softening point is 10°C or more selected. The total amount of such light stabilizers is 0.01% of the olefin resin.
It is blended in a proportion of ~2% by weight, preferably 0.1-0.8% by weight. The blending ratio of each light stabilizer is determined depending on the purpose such as the type of olefin resin and the degree of weather resistance. In addition, the composition of the present invention may contain fillers, pigment dispersants, and the like, if necessary.

In order to prepare a molded article using the composition of the present invention, the above-mentioned olefin resin, pigment, light stabilizer, and if necessary filler and dispersant are mixed, and using an extruder etc., a conventional method is used. Shaped by Usually, a pellet-like masterbatch containing a high concentration of pigment is prepared and kneaded with an olefinic resin. For example, when obtaining polypropylene artificial turf,
First, a masterbatch pellet containing a pigment that produces a greenish color is prepared. This is blended with polypropylene resin, formed into a film at 240 to 260°C, stretched at 120 to 140°C, and subjected to split weave processing. moreover
Heat treated at 130-150℃ and twisted with a twist rate of 15-55. Cut this to the desired length (14 to 60 mm), with a vertical density of 1.0 to 3.0 pieces/cm, and approximately 10 × 10 ³ to 70 × 10 ³
Hair is transplanted at a ratio of denier (D)/cm ² . In this way, a desired molded body is prepared.

Since the composition of the present invention uses a surface-treated inorganic pigment whose surface is coated with silicon oxide and/or silicon hydroxide, partition walls are formed between the inorganic pigment and the olefin resin. Therefore,
There are substantially no free transition metal ions in the molded article, and even if an inorganic pigment that promotes deterioration of olefin resins, such as synthetic iron oxide, is used, the deterioration of the resin will not be accelerated. Even when adding an organic pigment, a pigment with a low concentration of free transition metal ions in the pigment is used as described above, and since the organic pigment itself has no effect of substantially deteriorating the olefin resin, the resulting molding The body has excellent weather resistance.

Furthermore, since it contains two types of light stabilizers with different softening points, the pigments and light stabilizers that precipitate from the resin during molding and processing as described above may be removed from the molding die.
It does not adhere to heat set plates and has excellent moldability. In the obtained molded product, the light stabilizer with a lower softening point migrates to the surface of the molded product at a relatively early stage and exerts its function. A small amount of the low softening point light stabilizer and the high softening point light stabilizer remaining inside the molded body gradually migrates to the surface of the molded body. Therefore, the stabilizing effect of the olefin resin can be obtained for a long period of time.

(Example) The invention will be explained below with reference to examples.

Example 1 (A) Preparation of masterbatch pellets: [Masterbatch composition] Ingredient parts by weight (surface-treated inorganic pigment) Surface-treated synthetic iron oxide 20.6 (organic pigment) Copper phthalocyanine green 2.0 (free copper ion concentration: 40 ppm) (Free iron ion concentration: 10ppm or less) Isoindolinone Yellow 4.1 (Free copper ion concentration: 10ppm or less) (Free iron ion concentration: 10ppm or less) Polycondensed Azoret 0.3 (Free copper ion concentration: 10ppm or less) (Free iron Ion concentration: 10ppm or less) Carbo black 0.1 (Free copper ion concentration: 10ppm or less) (Free iron ion concentration: 18ppm or less) (Dispersant) Low molecular weight polyethylene 16.4 (Light stabilizer) Dimethyl-1-(2-hydroxy succinate) ethyl)-4-hydroxy-2,2,6,6-
Tetramethylpiperidine polycondensate (softening point 55
~70℃) 8.4 N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine polycondensate (MW2000; softening point 93-98
℃) 1.4 (Olefin resin) Polypropylene pellets (Chitsuso Co., Ltd. #5014)
44.9 The above masterbatch composition was premixed for 5 minutes using a Henschel mixer, and then melt-extruded using a vent-type extruder at 220 to 240°C to form pellets to obtain a green masterbatch for polypropylene artificial turf.

In the above composition, the surface-treated synthetic iron oxide pigment is obtained by finely dispersing a zinc ferrite-based synthetic iron oxide pigment in water, adding dropwise an aqueous sodium silicate solution and a dilute aqueous sulfuric acid solution thereto and stirring, followed by washing with hot water. , washed with water and dried.
This surface treatment synthetic iron oxide is the raw material synthetic iron oxide.
The silicon oxide and/or silicon hydroxide is contained in an amount of 30 parts by weight per 100 parts by weight.

The above-mentioned copper phthalocyanine green pigment and polycondensed azoretz pigment are synthesized by a conventional method, and then
It was obtained by finely dispersing it in water, adding dilute sulfuric acid, stirring, filtering, washing with hot water, further washing with water, drying and pulverizing.

(B) Preparation of olefin resin molded body (artificial turf):
1 part by weight of masterbatch pellets obtained in section (A) and polypropylene pellets (Chitsuso Co., Ltd.)
#5014) 17 parts by weight are kneaded (the concentration of free transition metal ions in this composition is 0.07 ppm or less based on the weight of polypropylene), and the molding temperature is 240 ~
Film formation was performed at 260°C using the isoflation method.
The obtained sheet was stretched approximately 5 times on a heating roll at 130 to 150°C, and subjected to a split weaving process using a splitter. Furthermore, heat treatment was carried out using a heating furnace and a heat roll so that the thermal shrinkage rate at 130° C. was within 10% to obtain split fibers with a thickness of 60 μm and 8000 denier (D). This was twisted at a twist rate of 27. The twist rate is expressed by the following formula: K=T√D/100 (twist rate) where D is the denier and T is the number of twists (turns/m).

Cut this fiber into a length of 45mm, 2.4 fibers/cm
The fibers were flocked on a polypropylene base fabric weighing 100 g/m ² with a longitudinal density of 100 g/m 2 and a density of 24×10 ³ D/cm ² . As a result, artificial turf with a fiber length of 20 mm was obtained.

(C) Performance evaluation of compositions and molded objects: In the above artificial turf manufacturing process, the adhesion of resins, pigments, light stabilizers, etc. to extrusion molds and stretching rolls during film formation and stretching is confirmed after 48 hours of operation. was hardly recognized. There was almost no yarn breakage or winding around the rolls, and the production efficiency was over 90%.

The weather resistance of the obtained artificial turf was evaluated using a weatherometer. After 1,600 hours had passed from the start of the test, the rough surface of #100 sandpaper was brought into close contact with the artificial turf surface and rubbed 10 times with a load of 1 kg, but no powdering of the resin was observed. Next, another test piece of new artificial turf was immersed in warm water at 80℃ for 6 hours, and a weather resistance test was conducted using it in the same manner as above.As a result, the resin remained powdery even after 1100 hours had passed since the start of the test. was not recognized.

Comparative Example 1 (A) Preparation of masterbatch pellets: A masterbatch composition having the same composition as in Example 1 was obtained except that only the following compound was used as a light stabilizer.

(Stabilizer) Dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-
Tetrapiperidine polycondensate (softening point: 55-70
°C) 9.8 parts by weight (B) Preparation of olefin resin molding (artificial turf):
Artificial turf was prepared in the same manner as in Example 1 using the composition of Comparative Example (A), and the performance of the resulting product was evaluated.

(C) Performance evaluation of molded product: When the weather resistance of the molded product obtained in Comparative Example (B) was examined using a weatherometer, deterioration (powderization) was observed within 1000 hours.

Comparative Example 2 (A) Preparation of masterbatch pellets: Example 1 except that the following compound was used as a light stabilizer:
A masterbatch composition having the same composition was obtained.

(Light stabilizer) Bis(2,2,6,6-tetramethyl-4-
piperidine) sebacate (MW480: Softening point: 85°C) 9.8 parts by weight (B) Preparation of olefin resin molding (artificial turf):
1 part by weight of the master batch pellets obtained in Comparative Example (A) and 17 parts by weight of polypropylene pellets (Chitsuso Co., Ltd. #5014) were kneaded, and the molding temperature was
The film was formed using an inflation method at 260°C.
The obtained sheet was stretched about 5 times on a heated roll and split by a splitter. Further, heat treatment was performed using a heating furnace at 130 to 150°C and a heat roll so that the thermal shrinkage rate at 130°C was within 10% to obtain split fibers of 8000 denier (D). This fiber is twisted at a rate of 35 times/m,
Flocking was performed using a tufting machine onto a polypropylene base fabric weighing 100 g/m ² . As a result, 24×
Artificial grass with a fiber length of 20 mm was obtained at 10 ³ D/cm ² .

(C) Performance evaluation of molded product: In a weather resistance test using a weatherometer using the molded product obtained in section (B) of this comparative example, no deterioration was observed 1500 hours after the start of the test. However, for the test piece treated with hot water in the same manner as in Example 1, significant deterioration was observed after 500 hours.

Comparative Example 3 (A) Preparation of masterbatch pellets: Example 1 except that the following compound was used as a light stabilizer:
A masterbatch composition having the same composition was obtained.

N,N'-bis(2,2,6,6-tetramethyl-4-piperidine)hexamethylenediamine polymer (MW2000: Softening point: 93-98℃)
9.8 parts by weight (B) Preparation of olefin resin molded object (artificial turf):
Using the masterbatch pellets obtained in Comparative Example (A), artificial turf was prepared according to the method of Comparative Example 2.

(C) Performance evaluation of composition and molded article: When using the composition of this comparative example, during film-forming extrusion, the light stabilizer and pigments (surface-treated synthetic iron oxide and some organic pigments) Adhesion started to occur after about 30 minutes, and the yarn broke during stretching. The production efficiency after 48 hours of operation was 83%.

In a weather test using a weatherometer, no deterioration was observed 1,500 hours after the start of the test.
Furthermore, no significant deterioration was observed in the test piece treated with hot water in the same manner as in Example 1 within 1200 hours.

Comparative Example 4 (A) Preparation of masterbatch pellets: Example 1 except that the following compound was used as a light stabilizer:
A masterbatch composition having the same composition was obtained.

(Light stabilizer) Poly[(6-(1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-
2,4-piperidyl][2,2,6,6-tetramethyl-4-piperidine)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino] (MW2500 or more: Softening Point: 100-135℃) 9.8 parts by weight (B) Preparation of olefin resin molded object (artificial turf):
Using the masterbatch pellets obtained in Comparative Example (A), artificial turf was prepared according to the method of Comparative Example 2.

(C) Performance evaluation of composition and molded article: When using the composition of this comparative example, during film-forming extrusion, the light stabilizer and pigments (surface-treated synthetic iron oxide and some organic pigments) Adhesion started to occur after about 30 minutes, and the yarn broke during stretching.

In a weather test using a weatherometer, no deterioration was observed 1,300 hours after the start of the test.
Furthermore, no significant deterioration was observed in the test piece treated with hot water in the same manner as in Example 1 within 1100 hours.

(Effects of the Invention) As described above, according to the present invention, a colored olefin resin composition can be obtained that is colored in a desired color and from which an olefin resin molded article having excellent weather resistance can be prepared. The moldability when preparing a molded article using the composition is also good. Since this composition uses pigments that are non-toxic or low-toxic to living organisms, it does not pollute the environment. The resulting molded product is particularly useful for products installed outdoors, such as artificial turf, agricultural films, and miscellaneous ropes.

Claims (1)

[Claims] 1. An olefin resin, a surface-treated inorganic pigment whose surface is coated with silicon oxide and/or silicon hydroxide, and a light stabilizer with the highest softening point and light with the lowest softening point. A colored olefin resin composition containing at least two light stabilizers whose softening points differ by 10°C or more from the stabilizer. 2. The composition according to claim 1, further comprising an organic pigment, wherein the concentration of free transition metal ions contained in the system is 1 ppm or less based on the weight of the olefinic resin. 3 The surface-treated inorganic pigment is the inorganic pigment 100
The composition according to claim 1, which contains silicon oxide and/or silicon hydroxide in an amount of 10 to 100 parts by weight. 4. The composition of claim 2, wherein the free transition metal ions originate primarily from an organic pigment. 5 The free transition metal ion concentration in the organic pigment is
The composition according to claim 4, which has a content of 100 ppm or less. 6. The composition according to claim 1, wherein the inorganic pigment is an iron oxide pigment. 7. The composition according to claim 2, wherein the transition metal ion is a copper ion.