JPH1180383A - Polyolefin film and support for photographic printing paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a support for a photographic printing paper excellent in smoothness, whiteness, resistance to discoloration under light, resistance to weathering discoloration, etc., especially excellent in covering effect on the basement and capable of improving the image quality of the layer formed on the surface by using a titan oxide-containing master batch which is excellent in dispersion and hydrophobicity, and little in the generation of water on a high temperature processing. SOLUTION: This polyolefin film comprises titanium oxide 1 which is treated with 0.05-3.0 wt.% of at least one kind of hydrophobic agent selected from the group consisting of silicone oils, titanium coupling agents and silane coupling agents, and has particle sizes of 0. 05-0. 20 μm and a bulk density of 0.27-0.35 g/cc, and a polyolefin resin 2. Further, the film has a porosity coefficient of 0.1-0.65.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support for photographic printing paper obtained by melt-extruding and laminating a polyolefin-based resin composition containing titanium oxide on at least one surface of a substrate such as paper. The present invention relates to a photographic printing paper support excellent in hiding properties, smoothness, whiteness, light discoloration resistance, and weather discoloration resistance.

[0002]

2. Description of the Related Art Conventionally, as a material used for a support for photographic printing paper, titanium oxide having excellent whiteness and concealing properties is contained in order to conceal a base and to enhance the quality of an image formed on the surface. Polyolefin-based resin compositions have been used.

[0003] Although titanium oxide is excellent as a white pigment, it has water of crystallization and, because of its hydrophilicity, adsorbs a large amount of water. No concealability was obtained. Various surface treatments with inorganic or organic substances have been performed to prevent aggregation of titanium oxide particles and improve dispersibility. However, sufficient dispersibility was not obtained by the conventional surface treatment.

For example, in the case of titanium oxide treated with a polyol-based surface treating agent, since the chemical bonding force between the surface of the titanium oxide and the treating agent is weak, a master using the surface-treated titanium oxide and a thermoplastic resin is used. The surface treatment agent peels off due to kneading conditions and extrusion conditions when manufacturing the batch,
The dispersion state of the titanium oxide in the masterbatch varied, and the water content increased due to a decrease in hydrophobicity. In addition, the above-mentioned titanium oxide, which has been insufficiently treated, causes secondary agglomeration, generates voids similar to air bubbles in a molded product such as a film, and causes a reduction in concealing properties and weakening of the film itself. Had become.

[0005] A masterbatch is one of the coloring compositions used for coloring and molding a thermoplastic resin. A masterbatch is prepared by dispersing a pigment at a high concentration in a solid resin at room temperature to form pellets or flakes. It is superior to other (powder, granule, flake, etc.) coloring compositions in terms of ease of handling and preservation of the working environment during use.

Generally, a colored molded product is obtained by melting and kneading a master batch and a thermoplastic resin for dilution, and extruding or injection molding. The support for photographic paper is
A master batch and a polyolefin resin for dilution are melted and kneaded, an olefin film is extruded onto a base material such as paper, and at least one surface of the base material is coated with an olefin film (hereinafter, referred to as a base material). Such a method is called melt extrusion lamination). In recent years, in the field of photographic printing paper supports, there has been a strong demand for improved productivity, that is, high-speed processability during melt extrusion lamination, in accordance with demands for cost reduction. When the polyolefin-based resin composition is melt-extruded and laminated at a high speed, the thickness of the film becomes thin, and a problem arises that a desired concealing property cannot be obtained with the conventional titanium oxide content. In order to solve such a problem, a method of ensuring a desired hiding property by including a large amount of titanium oxide in a polyolefin-based resin composition has been attempted. However, various problems have occurred due to a large amount of water derived from a large amount of titanium oxide.

That is, in order to produce a colored resin molded product using a masterbatch containing a large amount of titanium oxide and having a high water content, and a thermoplastic resin such as a polyolefin resin for dilution, an extrusion machine is generally used. The masterbatch and the thermoplastic resin slip due to the moisture generated from the masterbatch inside, causing poor dispersion, or the moisture returns to the raw material supply port side of the processing machine, and the raw material can be supplied smoothly. Problems such as disappearance occur.

In particular, 280 to 3 where desorption of water of crystallization or the like occurs.
In the field of melt extrusion lamination such as photographic paper support which requires high-temperature processing such as 50 ° C., the water content is extremely important. As the water content increases, water evaporates when the film is extruded. In addition, there has been a problem that a phenomenon in which a net-like hole is formed in the film, that is, so-called racing occurs, and the film is not practically used. Further, there is also a problem that the organic material treated on the surface of titanium oxide is decomposed at the time of high-temperature processing and the dispersibility is reduced, so that the concealing property of the film is reduced and desired quality cannot be obtained.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to use a titanium oxide-containing masterbatch which is rich in dispersibility and hydrophobicity and has low moisture generated during high-temperature processing, and has smoothness, whiteness, light discoloration resistance, An object of the present invention is to provide a support for photographic printing paper which is excellent in weathering discoloration resistance and the like, particularly excellent in concealing property of a base, and can improve the image quality of a layer formed on the surface.

[0010]

That is, a first aspect of the present invention is to provide at least one compound selected from the group consisting of a silicone oil, a titanium coupling agent and a silane coupling agent.
The particles having a particle diameter of 0.05 to 0.20 μm and a bulk density of 0.1 to 0.3 μm after being treated with 0.05 to 3.0% by weight of a hydrophobizing agent.
It contains 27 to 0.35 g / cc of titanium oxide (1) and polyolefin resin (2), and has a porosity coefficient of 0.1.
~ 0.65.

According to a second aspect, the silane coupling agent comprises:
The polyolefin film according to the first invention, which is an aminosilane coupling agent.

The third invention is characterized in that before the treatment with the hydrophobizing agent, 0.01 to 0.3% by weight of aluminate and / or 0.01 to 0.5% of calcium oxide is calculated.
The polyolefin film according to the first or second aspect, further comprising titanium oxide which is treated with a calcium salt by weight.

[0013] A fourth aspect of the present invention relates to at least one type of hydrophobizing agent selected from the group consisting of silicone oil, titanium coupling agent and silane coupling agent.
It contains titanium oxide (1) having a particle diameter of 0.05 to 0.20 μm and a bulk density of 0.27 to 0.35 g / cc, and a polyolefin resin (2). The polyolefin resin composition (3) to be melt-extruded and laminated on a base material has a porosity coefficient of 0.1 to 0.65.
A support for photographic printing paper, wherein the substrate is coated with a polyolefin film as described above.

According to a fifth aspect, the silane coupling agent is
The photographic printing paper support according to the fourth invention, which is an aminosilane coupling agent.

[0015] A sixth aspect of the present invention is to provide a method for treating a hydrophobizing agent,
It is characterized by containing titanium oxide which is treated with 0.01 to 0.3% by weight of aluminate in terms of alumina and / or 0.01 to 0.5% by weight of calcium salt in terms of calcium oxide. A photographic printing paper support according to the fourth or fifth invention.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Examples of the hydrophobizing agent used in the present invention include silicone oil typified by alkylpolysiloxanes, a titanium coupling agent and a silane coupling agent. Particularly effective for the hydrophobizing treatment is a silane coupling agent, for example, an alkoxysilane having an alkyl group, an alkenyl group, an amino group, an aryl group, an epoxy group or the like, a chlorosilane, or a polyalkoxyalkylsiloxane is more preferable. It is an aminosilane coupling agent. The hydrophobizing agent is used to improve the hydrophobicity, dispersibility, and affinity with the olefin resin of the titanium oxide by physically adsorbing or chemically reacting with the hydroxyl groups on the titanium oxide surface. Although the reason is not clear yet, the concealment property can be improved.

The silane coupling agent includes, for example, N-β
(Aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyltrimethoxysilane, N-β (aminoethyl) γ-
Aminosilane coupling agents such as aminopropylmethyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane,
Dimethyldimethoxysilane, methyltrimethoxysilane,
Examples thereof include alkylsilane coupling agents such as ethyltrimethoxysilane and propyltrimethoxysilane, and these can be used alone or in combination of two or more.

Titanium oxide is used as the above-mentioned hydrophobizing agent 0.05 to
3.0% by weight, preferably 0.05 to 1.0% by weight, more preferably 0.1 to 1.0% by weight.
It is formed by treating with 0.5% by weight. 3.0% by weight
If the ratio exceeds the above range, slip occurs at the time of extrusion and the ejection of the material becomes unstable, so that the colored composition cannot be manufactured stably. In particular, in the case of a film, the film thickness becomes non-uniform or the film breaks, making molding impossible. On the other hand, if the content is less than 0.1% by weight, the effect of hydrophobizing titanium oxide is small, and moisture adsorption over time after the production of the masterbatch increases, causing the same problem as in the past.

The calcium salt used in the present invention is used for fixing the hydroxyl group by reacting with the hydroxyl group on the surface of the titanium oxide and hydrophobizing the titanium oxide in the same manner as the above-mentioned hydrophobizing agent. Examples of such calcium salts include calcium chloride, calcium bromide, calcium iodide, calcium sulfate and the like.

The amount of the calcium salt to be treated is 0.01 to 0.5% by weight in terms of calcium oxide. If the treatment amount is less than 0.01% by weight, the effect of hydrophobization is insufficient, and if the amount is more than 0.5% by weight, the effect of hydrophobization hardly changes.

In the present invention, the treatment with the hydrophobizing agent and the treatment with a calcium salt or the like can be used in combination to fix the hydroxyl groups on the surface of the titanium oxide.

In the present invention, the treatment with a hydrophobizing agent such as a silane coupling agent may be used in combination with the treatment with a calcium salt or the like, or the treatment with a hydrophobizing agent such as a silane coupling agent and the treatment with an aluminate may be used. The treatment with a hydrophobizing agent such as a silane coupling agent, the treatment with a calcium salt or the like, and the treatment with an aluminate may be used in combination. That is, after treating titanium oxide with a calcium salt or the like, it may be treated with a hydrophobizing agent such as a silane coupling agent, or after treating titanium oxide with an aluminate, a hydrophobizing agent such as a silane coupling agent may be used. Alternatively, the titanium oxide may be treated with a calcium salt, then treated with an aluminate, and further treated with a hydrophobizing agent such as a silane coupling agent.

Alumina generally contains water of crystallization,
Although it is hydrated, it is preferable to reduce as much as possible from the viewpoint of reducing moisture, but in a field where strong concealment is required, it is preferable to contain as little alumina as possible, and titanium oxide Is preferably 0.3% by weight or less, more preferably 0.2% by weight or less. If it exceeds 0.3% by weight, the water content increases, and troubles during processing are liable to occur.

The titanium oxide used in the present invention is:
Aluminum may be contained in the crystal in order to prevent discoloration to bluish black during high temperature processing.
It is preferred that the content be contained by weight.

The treated titanium oxide used in the present invention has a primary particle size of 0.05 to 0.20 by electron microscopy.
μm is preferred. When the content is in the above range, the concealing property is improved, and when it is out of the range, poor dispersion or the like is caused, the concealing property is reduced, and the desired quality is not achieved.

The treated titanium oxide used in the present invention has a bulk density of 0,0 determined according to JIS K5101.
27 to 0.35 g / cc. Within the above range,
Although the cause is not yet clear, it is considered that the porosity coefficient of the film is lowered due to having a suitable bulk density, and as a result, the concealing property is improved.

In the present invention, the porosity coefficient of the polyolefin film for photographic printing paper refers to the ratio of bubble-like voids formed around one titanium oxide particle (TiO2 particle) dispersed in the film. Depending on the dispersibility of the titanium oxide particles and the degree of affinity between the surface of the titanium oxide particles and the polyolefin-based resin, the porosity coefficient changes, and if the dispersibility is good and / or the affinity is good, the porosity coefficient becomes small and concealment occurs. It is preferable because the property is improved.

The porosity coefficient of the polyolefin film is
It needs to be 0.1 to 0.65. If it is larger than 0.65, the concealing property is reduced. It is considered that the large porosity coefficient indicates that the titanium oxide particles have strong secondary agglomeration, and the secondary agglomeration narrows the particle interval and makes it easier to transmit visible light, so that the concealing property is reduced. On the other hand, when the porosity coefficient is smaller than 0.1, the film is practically equivalent to a film having no titanium oxide particles in the film, and cannot be used because it has no concealing property.

The titanium oxide used in the present invention may be either rutile type or anatase type.
Although both may be used in combination, the anatase type is preferred from the viewpoint of whiteness.

When neither treatment with a hydrophobizing agent such as a silane coupling agent or treatment with an aluminate or calcium salt is performed, the dispersion of titanium oxide is extremely poor, and the colored resin molded product Agglomerates are generated therein and clogging of the screen mesh of the molding machine is caused.

The polyolefin film of the present invention contains the treated titanium oxide (1) and the polyolefin-based resin (2), and the treated titanium oxide (1) and the polyolefin-based resin (2-a) are mixed in advance. / 8 to 8/2,
Preferably 5/5 to 7/3, more preferably 6/4 to
At a ratio of 7/3, a pelletized masterbatch (coloring composition) obtained by melt-kneading was obtained, and the obtained masterbatch and the polyolefin resin (2-b) for dilution were combined with 1: 1.
It is preferable to melt-knead at a ratio of / 9 to 9/1 and form a film.

The masterbatch used in the present invention has a water content capable of volatilizing at 280 to 350 ° C. is 1200 pp.
m or less, more preferably 280-350 ° C
Is preferably 800 ppm or less, most preferably 300 ppm or less. If the moisture that can be volatilized at 280 to 350 ° C. is more than 1200 ppm, the photographic printing paper support is obtained by melt lamination using the master batch and the polyolefin resin (2-b) as described above. Various problems arise. The moisture is the amount of moisture generated at a predetermined temperature under a nitrogen atmosphere using a Karl Fischer moisture meter.

The polyolefin resin (2) used in the present invention may be a general polyolefin resin such as a polyethylene resin or a polypropylene resin, and the film for photographic printing paper may be a masterbatch resin. It is preferable that both the polyolefin resin (2-a) and the polyolefin resin (2-b) for dilution are polyethylene resins.

The photographic printing paper support of the present invention is obtained by subjecting a polyolefin resin composition (3) containing a treated acid value titanium (1) and a polyolefin resin (2) to melt extrusion lamination on a substrate. It is.

The paper or synthetic paper used as the base material in the present invention may be any of natural pulp, synthetic pulp, a mixture thereof and the like, but natural pulp is preferred. The paper thickness is about 20 to 400 μm, preferably 70 to 250 μm, and a paper having a smooth surface is preferable. Further, the basis weight is preferably about 15 to 350 g / m ² , and 50 to 250 g.
/ M ² is more preferred.

The photographic printing paper support of the present invention is formed by slitting a melt of a polyolefin resin composition (3) using a masterbatch and a polyolefin resin (2-b) on running paper or synthetic paper. It is manufactured by extrusion lamination from a die into a film. The melt extrusion temperature at that time is 250 to 350 ° C, preferably 280 to 320 ° C.

The thickness of the coating layer of the photographic printing paper support of the present invention is about 5 to 200 μm, preferably 5 to 50 μm, more preferably 5 to 20 μm.

The polyolefin-based resin composition (3) for a photographic printing paper support of the present invention may contain other optional pigments, ultraviolet absorbers, etc. as long as the effect is not impaired other than the above components. Can be added as needed.

[0039]

The present invention will be described below in detail with reference to examples and comparative examples. Examples 1 to 7, Comparative Examples 1 to 4 Low density polyethylene (specific gravity 0.917, MFR 7.0 g / 10 min.) 4
0% by weight and 60% by weight of titanium oxide having different treatments shown in Table 1 were mixed, heated and mixed by a kneader, cooled and pulverized, and then extruded by an extruder to obtain a pelletized master batch. Various evaluations were performed using the obtained master batch. The evaluation method is shown below, and the results are shown in Table 1.

Moisture Measurement Method 1 g of the above masterbatch was measured for the amount of water generated at each temperature using a Karl Fischer moisture meter (manufactured by Hiranuma Sangyo). Unit: ppm

Dispersibility evaluation method Labo Plastomill single screw extruder 20 mm (manufactured by Toyo Seiki)
At 40/80/120/500 at the outlet of the above, a screen with a finer mesh was attached in sequence, and at 50 rpm and an extrusion temperature of 300 ° C., low density polyethylene (specific gravity 0.916, MFR 9.
0g / 10min.) And the master batch are passed through a pellet blended at a ratio of 1: 1 to determine the initial pressure (P1) at the start of the passage, and the pellet blended at a ratio of 1: 1 is added to a predetermined amount (titanium oxide in the pellet). End pressure (P2) at the time of passing through an amount of 360 g). This pressure difference ΔP = P2
It can be said that the smaller the -P1 is, the better the dispersibility of the titanium oxide is.

T-die film forming method 67% by weight of the master batch and 33% by weight of low density polyethylene (specific gravity 0.918, MFR 4.0g / 10min.)
Using a T-die film molding machine (manufactured by Toyo Seiki), a 30-μm-thick T-die film was melt-extruded and laminated on paper at a molding temperature of 300 ° C., and the film-forming properties (appearance, etc.) were evaluated.

Evaluation of film formability: Visual evaluation of the presence or absence of lacing, etc. A: No lacing or foaming. ：: There are racing and some foaming. Δ: Racing and foaming. X: Lacing and foaming are remarkable and film formation is impossible.

Evaluation of concealability 20% by weight of the above master batch, low density polyethylene 8
0% by weight was blended, and the transmittance at each wavelength was measured using a colorimeter (manufactured by Kurabo Industries Co., Ltd.) for a 30 μm film extruded at a molding temperature of 300 ° C. so that the titanium oxide content was 12% by weight. The result is as shown in Table 1. The lower the transmittance, the better the concealing property, and the larger the transmittance, the worse the concealing property.

The photographic properties of the melt-extruded laminate film extruded at 300 ° C. were evaluated.
Examples 1 to 7 were excellent.

Measurement of Porosity of Film The porosity coefficient of the film used in the evaluation of the hiding power is shown in Table 1. Here, the porosity coefficient of the film is [1- (specific gravity of film / ideal specific gravity of film)] × 100 ° (weight% of titanium oxide contained in the film). However, the ideal specific gravity of the film is: titanium oxide content / titanium oxide specific gravity +
[(1- titanium oxide content) / polyethylene specific gravity], and polyethylene is low density polyethylene (specific gravity 0.916)
And

In the evaluation of the film forming property, the concealing property and the porosity coefficient, the content of the acid value-treated titanium oxide was appropriately selected so that the difference in the treated acid value titanium could be more easily grasped.

[0048]

[Table 1]

[0049]

According to the present invention, excellent high-speed and high-temperature workability is achieved.
It has become possible to provide a polyolefin-based film and a support for photographic printing paper, which are particularly excellent in concealing property and more excellent in whiteness, heat discoloration resistance, weather discoloration resistance and light discoloration resistance than before.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // G03C 1/79 G03C 1/79 B29K 23:00 B29L 7:00

Claims (6)

[Claims] 1. A particle size obtained by treating with 0.05 to 3.0% by weight of at least one hydrophobizing agent selected from the group consisting of silicone oil, titanium coupling agent and silane coupling agent. Titanium oxide (1) having a bulk density of 0.27 to 0.35 g / cc.
And a polyolefin-based resin (2), wherein the porosity coefficient is 0.1 to 0.65. 2. The polyolefin film according to claim 1, wherein the silane coupling agent is an aminosilane coupling agent. 3. Prior to treatment with a hydrophobizing agent, 0.01 to 0.3% by weight of aluminate in terms of alumina and / or 0.01 to 0.5% by weight of calcium salt in terms of calcium oxide. 3. The polyolefin film according to claim 1, further comprising a titanium oxide obtained by the treatment. 4. A particle size of 0.05 to 3.0% by weight of at least one hydrophobizing agent selected from the group consisting of silicone oil, titanium coupling agent and silane coupling agent. Titanium oxide (1) having a bulk density of 0.27 to 0.35 g / cc.
And a polyolefin-based resin composition (3) containing the polyolefin-based resin (2) are melt-extruded and laminated on a base material, and the base material is coated with a polyolefin film having a porosity coefficient of 0.1 to 0.65. A photographic printing paper support characterized by being coated. 5. The photographic printing paper support according to claim 4, wherein the silane coupling agent is an aminosilane coupling agent. 6. Prior to treatment with a hydrophobizing agent, 0.01 to 0.3% by weight of aluminate in terms of alumina and / or 0.01 to 0.5% by weight of calcium salt in terms of calcium oxide. The photographic printing paper support according to claim 4 or 5, wherein the support contains oxidized titanium oxide.