JPH11246222A - Titanium dioxide pigment composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a titanium dioxide pigment-contg. resin compsn. which suppresses the occurrence of gum in melt extrusion coating. SOLUTION: The compsn. for an image recording substrate consists essentially of a titanium dioxide pigment and a polyolefin resin and further contains 0.03-2.0 pts.wt., based on 100 pts.wt. titanium dioxide pigment, binary copolymer of vinylidene fluoride and hexafluoropropylene and/or ternary copolymer of the binary copolymer and tetrafluoroethylene and has 3-20 g/10' melt index. The average particle diameter of the titanium dioxide pigment compsn. and the titanium dioxide pigment is 0.01-0.5 μm. The occurrence of gum can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium dioxide pigment used for producing an image-recording support such as a photographic paper for silver salt photography and a recording medium for hard copy of a computer image by a melt extrusion coating method. The present invention relates to a composition, and more specifically, to provide a composition excellent in moldability with extremely few occurrences of "eyes" in melt extrusion coating.

[0002]

2. Description of the Related Art Conventionally, in the production of photographic paper for silver halide photography and recording media for hard copy, a composition comprising a polyolefin resin and a titanium dioxide pigment is applied to paper or a film of polyester or the like as a base material. It is common practice to apply a melt-extrusion coating continuously after heating to obtain a support having excellent water resistance. At this time, the titanium dioxide pigment is used in the form of a so-called masterbatch previously contained in polyethylene at a high concentration, and is used by being mixed with a diluting resin so as to have a finally required concentration. In such a melt extrusion coating process, a molding method generally called lamination is used. In this molding method, the occurrence of "eyes and eyes" in the die portion leads to the occurrence of surface defects of the molten film, which is a fatal problem in stable operation.

Several approaches have been taken to solve this problem. For example, JP-A-58-17
No. 433, a method of treating the particle surface of a titanium dioxide pigment with a divalent to tetravalent alcohol, JP-B-59-42296.
Are (1) a polyolefin resin, (2) titanium dioxide having a loss on drying at 110 ° C. for 2 hours of 0.35% or less;
(3) A polyolefin resin composition comprising a higher fatty acid metal salt, and JP-B-61-39335 discloses that 0.1 to 20 parts by weight of zinc oxide is added to 100 parts by weight of a polyolefin composition containing titanium dioxide. And 0.01 to 2 parts by weight of a dispersing agent such as a metal salt of a higher fatty acid, a metal salt of an alkyl sulfate or an alkyl sulfate ester salt. , the amount of aluminum to titanium dioxide during the oxidation step in the chloride process is 0.1 in terms of Al ₂ O ₃
A method is described in which, after an aluminum compound is added so as to be 2.0% by weight, a sulfuric acid method is produced through a firing step.

[0004]

In the above prior art,
It was difficult to sufficiently suppress the occurrence of "eye flaws". Therefore, in the present invention, when producing a resin-coated medium for image recording, a titanium dioxide pigment which can be suppressed to a sufficiently satisfactory level, which is generated when a polyolefin resin composition containing titanium dioxide is melt-extruded and applied. It is to provide a composition.

[0005]

Means for Solving the Problems The present inventors have made intensive efforts to solve the above-mentioned problems, and as a result, a composition for an image recording support mainly comprising a titanium dioxide pigment and a polyolefin resin, comprising titanium dioxide 0.03 to 2.0 parts by weight of a binary copolymer of vinylidene fluoride and hexafluoropropylene and / or a terpolymer of the binary copolymer and ethylene tetrafluoride with respect to 100 parts by weight of the pigment. And the composition has a melt index of 3 to 20.
g / 10 minutes, and the titanium dioxide pigment composition has an average particle size of 0.01.
A titanium dioxide pigment composition characterized by a size of .about.0.5 microns has been found. As a result, "eyes and eyes" could be reduced.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The titanium dioxide pigment used in the present invention may be one produced by a chlorine method or a sulfuric acid method, and the crystal form thereof may be rutile or anatase. However, the average particle size of the titanium dioxide pigment is preferably 0.01 to 0.5 microns. If the particle size is less than 0.01 micron, the coagulation in the process of handling the titanium dioxide pigment becomes severe, and the surface activity becomes remarkable, which promotes the deterioration of the polyolefin resin and increases the number of defects caused by the coagulation in the lamination process. When the average particle diameter exceeds 0.5 μm, the light concealing property is remarkably deteriorated, and the optical characteristics as an image recording support are significantly deteriorated. Regarding the surface treatment of titanium dioxide, it is more preferable to use any one of inorganic oxides such as aluminum oxide, silicon oxide, and zirconium oxide or a product treated with a hydrate thereof. Some of the objects may be processed sequentially or simultaneously, but
In particular, those treated with an inorganic substance containing hydrous aluminum oxide are desirable. In addition, after treatment with such an inorganic substance, trimethylolpropane, a polyol such as pentaerythritol or triethanolamine,
Those treated with an organic substance such as an alkanolamine such as an organic acid salt of trimethylolamine, a silicone oil, or a silicon compound such as an alkylchlorosilane are more preferable.

[0007] The polyolefin resin used in the present invention refers to a polymer of an ethylenically unsaturated hydrocarbon, and includes low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, and ethylene-propylene copolymer (random). Or a block copolymer), polystyrene and the like, and low-density polyethylene is preferable because of its excellent workability at high temperatures.

The binary copolymer of vinylidene fluoride and hexafluoropropylene used in the present invention may be a mixture of the binary copolymer and polyethylene glycol. The mixing ratio of polyethylene glycol in this case is
The content is preferably 70% by weight or less based on the binary copolymer. In the present invention, the terpolymer of the binary copolymer and ethylene tetrafluoride can be used alone or in a mixture with the above-mentioned binary copolymer. In the following, these copolymers are abbreviated as "binary and / or ternary copolymers".

According to the present invention, a binary or / and terpolymer is used in an amount of from 0.03 to 100 parts by weight of a titanium dioxide pigment.
2.0 parts by weight, and achieves a melt index of 3 to 20 g / 10 min. here,
The melt index refers to a value measured at a cylinder temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K7210. When the proportion of the binary or / and terpolymer is less than 0.03 parts by weight, it is not possible to suppress the occurrence of “eyes and eyes” during melt extrusion coating,
On the other hand, if it exceeds 2.0 parts by weight, the occurrence of "eye flaws" tends to increase. Even if the above-mentioned compounding ratio with respect to the titanium dioxide pigment is 0.03 to 2.0 parts by weight, at the same time, the melt index of the composition is 3 g / g.
If the time is less than 10 minutes, it is not possible to sufficiently suppress the occurrence of "eyes" during melt extrusion coating, and if the melt index value exceeds 20 g / 10 minutes, surging occurs during film formation, I cannot get a stable product. The ratio of the polyolefin contained in the composition of the present invention is not particularly limited, but generally, the polyolefin is preferably 30 to 900 parts by weight based on 100 parts by weight of the titanium dioxide pigment. If the polyolefin is less than 30 parts by weight, the fluidity during melting becomes poor,
When a polyolefin exceeds 900 parts by weight, the relative proportion of the titanium dioxide pigment decreases, so that the support obtained by melt extrusion coating becomes opaque. This is not preferable because the optical properties such as the properties are greatly deteriorated.

In the present invention, addition of various additives other than the titanium dioxide pigment, the polyolefin, and the binary or / and terpolymer to the composition is not prevented. For example, phenol-based, phosphorus-based, sulfur-based antioxidants, zinc stearate, metal stearate such as calcium stearate, magnesium stearate, etc., inorganic fillers such as silicon dioxide, zinc oxide, aluminum oxide, calcium carbonate, inorganic based An anti-adhesive agent and the like may be blended.

The method for obtaining the composition of the present invention includes titanium dioxide pigment, polyolefin, binary and / or
The raw material copolymer, if necessary, may be mixed with the above-mentioned other additives and then heated and kneaded and molded, or the titanium dioxide pigment and a binary or / and terpolymer may be added in advance and other additives as required. Or a mixture of the mixed powder and the polyolefin and then heat kneading and molding, or a compound obtained by melt-mixing a polyolefin with a binary or / and terpolymer and other additives in advance. , And then mixing the compound with a titanium dioxide pigment and subjecting the mixture to heat kneading and molding. When mixing is performed in these steps, a general high-speed shear mixer such as a Henschel mixer or a super mixer can be used. In addition, as a device used in the step of heating and melting and mixing, a pressure kneader, a Banbury mixer, a twin-screw kneading extruder,
Single-screw kneading extruders and the like can be mentioned. Of course, these may be used alone or in combination.

[0012]

The present invention will be described below with reference to examples. Example 1 Commercially available rutile type titanium dioxide pigment (R10 manufactured by DuPont)
1) 20 kg is put into a 75 L high-speed shearing mixer (Henschel mixer FM75 manufactured by Mitsui Miike Kakoki Co., Ltd.), and a binary copolymer of vinylidene fluoride and hexafluoropropylene (Dynamer P manufactured by Sumitomo 3M) is placed therein.
PA) 40 g and zinc stearate 700 g were added, and 3
Mixing was performed for 0 minutes. The mixed powder thus obtained and a low-density polyethylene (JALEX L170 manufactured by Nippon Polyolefin Co., Ltd.) were mixed with a commercially available single-shaft type such that the weight ratio of the low-density polyethylene to the mixed powder was 1: 3.82. The mixture was kneaded and extruded at a temperature of 120 ° C. using a kneading extruder (KCK35-80VEX) to obtain 25 kg of a pellet-shaped titanium dioxide pigment composition. The titanium dioxide pigment composition thus obtained was subjected to JIS K72 using a commercially available melt index measuring device (Takara X416) at a cylinder temperature of 190 ° C. and a load of 2.16 kg.
The melt index was measured in accordance with No. 10 and found to be 7.4. Next, a test was conducted on the obtained titanium dioxide pigment composition to examine the degree of occurrence of "eye fray" by the following method.

A 20 mm single screw extruder was mounted on a commercially available resin extrusion tester (Laboplast Mill, manufactured by Toyo Seiki Co., Ltd.), and a T-die having a width of 90 mm was mounted on the tip of the extruder. In addition, the temperatures of the single-screw extruder and the T-die were increased by 150 ° C, 250 ° C, 250 ° C, 250 ° C from the upstream side.
° C, 320 ° C, and 320 ° C. After the temperature reached a steady state, the titanium dioxide pigment composition was charged into a feed hopper and extruded at a screw rotation speed of 150 rpm. Extruded total amount of titanium dioxide pigment composition is 5
When the weight became kg, the number of "eyes" on the lip of the T-die was measured. When counting was performed by the above method, 2
It was a book.

Example 2 A commercially available rutile-type titanium dioxide pigment (R10 manufactured by DuPont)
1, average particle size 0.19 micron) 20 kg of internal volume 7
A 5-L high-speed shearing mixer (Henschel mixer FM75 manufactured by Mitsui Miike Kakoki Co., Ltd.) was placed therein, in which 200 g of a binary copolymer of vinylidene fluoride and hexafluoropropylene (Dynamer PPA manufactured by Sumitomo 3M) and zinc stearate were added. 700 g was added and mixed for 30 minutes.
The mixed powder thus obtained and a low-density polyethylene (JALEX L170 manufactured by Nippon Polyolefin Co., Ltd.) were mixed with a commercially available single-shaft type such that the weight ratio of the low-density polyethylene to the mixed powder was 1: 3.78. The mixture was extruded by a kneading extruder (KCK35-80VEX) and 25 kg of a pellet-shaped titanium dioxide pigment composition was obtained.
Obtained. For the titanium dioxide pigment composition thus obtained, a commercially available melt index measuring device (Takara X41)
Using 6), cylinder temperature 190 ° C, load 2.16kg
The melt index was measured according to JIS K7210 under the conditions described above, and it was 7.5. Next, the titanium dioxide pigment composition thus obtained was subjected to a test for examining the degree of occurrence of “eyes” by the method described in Example 1 and found to be one.

Example 3 A commercially available rutile type titanium dioxide pigment (R10 manufactured by DuPont)
1) 20 kg is put into a 75 L high-speed shearing mixer (Henschel mixer FM75 manufactured by Mitsui Miike Kakoki Co., Ltd.), and a binary copolymer of vinylidene fluoride and hexafluoropropylene (Dynamer P manufactured by Sumitomo 3M) is placed therein.
PA) 2 g and zinc stearate 700 g are added, and 30
Mixing was performed for minutes. The mixed powder thus obtained and a low-density polyethylene (JALEX L170 manufactured by Nippon Polyolefin Co., Ltd.) were mixed with a commercially available single-shaft type such that the weight ratio of the low-density polyethylene to the mixed powder was 1: 0.93. The mixture was kneaded and extruded by a kneading extruder (KCK35-80VEX) to obtain 25 kg of a pellet-shaped titanium dioxide pigment composition. The titanium dioxide pigment composition thus obtained was measured for melt index according to JIS K7210 at a cylinder temperature of 190 ° C. and a load of 2.16 kg using a commercially available melt index measuring device (Takara X416). It was 3. Next, the titanium dioxide pigment composition thus obtained was subjected to a test for examining the degree of occurrence of “eyes” by the method described in Example 1, and it was found that the number was four.

Example 4 A commercially available rutile type titanium dioxide pigment (R10 manufactured by DuPont)
1) Put 20 kg into a 75 L high-speed shearing mixer (Henschel mixer FM75 manufactured by Mitsui Miike Kakoki Co., Ltd.), add 700 g of zinc stearate and mix for 30 minutes to obtain a titanium dioxide pigment as a main component. To obtain a mixture. Then, in a high-speed shear mixer (Henschel mixer FM20 manufactured by Mitsui Miike Kakoki Co., Ltd.), 5 kg of low-density polyethylene resin pellets (JALEX L170 manufactured by Nippon Polyolefin Co., Ltd.) and a binary copolymer of vinylidene fluoride and hexafluoropropylene ( 100 g of Sumitomo 3M Dynamer PPA) was added and mixed for 15 minutes. The mixture thus obtained was melt-extruded at 150 ° C. using a single-screw extruder to obtain master pellets having a concentration of the binary copolymer of 2% by weight. Then, 38.7 kg per 1 kg of this master pellet
And low-density polyethylene (JALEX L170 manufactured by Nippon Polyolefin Co., Ltd.), and the mixed powder obtained above and the mixed pellet containing a fluoroelastomer were mixed at a weight ratio of the mixed pellet to the mixed powder of 1: 3.
82, a commercially available single-screw kneading extruder (KC
K35-80VEX) to obtain a pellet-shaped titanium dioxide pigment composition (25 kg). Using a commercially available melt index measuring device (Takara X416), the titanium dioxide pigment composition thus obtained was subjected to J at a cylinder temperature of 190 ° C. and a load of 2.16 kg.
The value of the melt index measured according to IS K7210 was 7.5. Next, the titanium dioxide pigment composition thus obtained was subjected to a test for examining the degree of occurrence of “eyes” by the method described in Example 1 and found to be one.

Example 5 Titanium dioxide pigment of anatase type (TCA123 manufactured by Tochem Products Co., Ltd., average particle size 0.17)
Micron) was used in the same manner as in Example 4 to prepare a titanium dioxide pigment composition. The melt index value of this composition was 8.5. The number of eyes was five.

Example 6 In Example 4, different grades of low-density polyethylene (JALEX L13 manufactured by Nippon Polyolefin Co., Ltd.)
A titanium dioxide pigment composition was obtained in the same manner except that 0) was used. The melt index value of this composition is 3.
The number of "eye eyes" was two.

Example 7 A titanium dioxide pigment composition was produced in the same manner as in Example 1 except that a polypropylene resin (LS712 manufactured by Nippon Polyolefin Co., Ltd.) was used in place of the low-density polyethylene of Example 1, and a titanium dioxide pigment composition was prepared. Evaluation 4 of "Eye and eye"
It was a book.

Comparative Example 1 Binary copolymer of vinylidene fluoride and hexafluoropropylene of Example 3 (Dynamer P manufactured by Sumitomo 3M)
A titanium dioxide pigment composition was prepared in the same manner as in Example 3 except that the amount of PA) was 4 g, and the melt index was measured. The result was 8.3. In addition, the number of eyes was "12".

Comparative Example 2 Binary copolymer of vinylidene fluoride and hexafluoropropylene of Example 2 (Dynamer P manufactured by Sumitomo 3M)
A titanium dioxide pigment composition was prepared in the same manner as in Example 2 except that the amount of PA) was 600 g, and the melt index was measured to be 7.9. The number of eyes was nine.

Comparative Example 3 Commercially available rutile type titanium dioxide pigment (R10 manufactured by DuPont)
1) 20 kg was put into a 75 L high-speed shearing mixer (Henschel mixer FM75 manufactured by Mitsui Miike Kakoki Co., Ltd.), 700 g of zinc stearate was added thereto, and the mixture was mixed for 30 minutes. A mixed powder was obtained. Next, 5 kg of low-density polyethylene resin pellets and 100 g of a binary copolymer of vinylidene fluoride and hexafluoropropylene (Dynamar PPA manufactured by Sumitomo 3M) were added to a high-speed shear mixer (Henschel mixer FM20 manufactured by Mitsui Miike Koki Co., Ltd.). And mixed for 15 minutes. The mixed powder thus obtained and a mixed pellet comprising low-density polyethylene and a fluoroelastomer were mixed at a weight ratio of the mixed pellet to the mixed powder of 1: 3.
82, a commercially available single-screw kneading extruder (KC
K35-80VEX) to obtain a pellet-shaped titanium dioxide pigment composition (25 kg). The titanium dioxide pigment composition thus obtained was measured for melt index and found to be 2.7. Next, about the obtained titanium dioxide pigment composition,
The number of occurrences was determined to be 10.

Comparative Example 4 The amount of the fluoroelastomer in Comparative Example 1 was 4 k.
Except for g, a titanium dioxide pigment composition was obtained in the same manner as in Comparative Example 1, and the value of the melt index was determined to be 2.7. In addition, the number of eyes
There were five. In the above, the ratio of the binary copolymer (abbreviated as “FEC”), the ratio of the polyolefin (abbreviated as “POC”) and the value of the melt index (abbreviated as “MI”) when the ratio of the titanium dioxide pigment is 100 Table 1 summarizes the number of eyes and eyes (abbreviated as “DL”).

[0024]

[Table 1]

[0025]

By using the titanium dioxide pigment composition according to the present invention, it is possible to use a melt extrusion coating method for producing an image recording support such as a silver salt photographic printing paper or a recording medium for hard copy of a computer image. It has become possible to suppress the occurrence of "eyes and eyes" to a sufficiently satisfactory level by a practical method.

Claims (2)

[Claims] 1. A composition for an image recording support comprising a titanium dioxide pigment and a polyolefin resin as main components,
Based on 100 parts by weight of the titanium dioxide pigment, a binary copolymer of vinylidene fluoride and hexafluoropropylene or / and a terpolymer of the binary copolymer and ethylene tetrafluoride
A titanium dioxide pigment composition comprising 0.03 to 2.0 parts by weight of a base copolymer and having a melt index of 3 to 20 g / 10 minutes. 2. The titanium dioxide pigment has an average particle size of 0.0
The titanium dioxide pigment composition according to claim 1, wherein the composition is 1 to 0.5 microns.