WO1994027186A1 - Resin-coated paper - Google Patents

Abstract

A resin-coated paper having on one side thereof a first resin layer comprising a resin composition having a critical shear rate of 10 sec-1 or less and prepared by melt mixing 90-65 parts by weight of a high-density polyethylene resin having a melt flow rate of 10.0-40.0 g/10 min and a density of 0.960 g/cm3 or above and 10-35 parts by weight of a low-density or medium-density polyethylene resin having a melt flow rate of 0.2-2 g/10 min, a density of 0.935 g/cm3 or less, a content of fractions having a molecular weight of 500 thousand or above of 10 wt.% or above and a critical shear rate of 0.5 sec-1 or less. This paper has a good moldability at the resin layer, is excellent in the adhesion between the resin layer and the base paper, and little forms gel.

Description

 Description Resin-coated paper [Technical field]

 The present invention relates to a paper substrate, in which one side of a paper substrate (hereinafter referred to as a base paper) on which an image forming layer is provided is formed of a resin composition containing a polyolefin resin as a main component. A support for image material, which is covered with a resin layer made of a resin composition composed of a resin composition mainly composed of a polyethylene-based resin, and optionally coated on the opposite side of the base paper surface. The present invention relates to a resin-coated paper which is preferably used. Specifically, there is no problem caused by transfer of dirt on the cooling roll, no gel-like foreign matter is generated in the resin layer on the side opposite to the side on which the image forming layer is provided, and curl properties and The present invention relates to a resin-coated paper-type image material support which has excellent cutability, adhesiveness between a base paper and the resin layer, and is capable of high-speed and stable production. (Background technology)

2. Description of the Related Art Conventionally, a resin-coated paper having at least one surface of a base paper coated with a film-forming resin for a support for an image material is well known. For example, Japanese Patent Publication No. 55-128584 describes a photographic support in which a base paper is coated with a film-forming resin, preferably a polyolefin resin. Techniques are disclosed. U.S. Pat. No. 3,501,298 discloses that both sides of a base paper are coated with a polyolefin resin. Techniques for photographic supports are disclosed. In addition, since the rapid photographic development of silver halide photosensitive materials was applied, photographic supports in which both sides of the base paper were coated with polyethylene resin have been used mainly for photographic printing paper. In general, a titanium dioxide pigment is contained in the resin layer on the image forming side of one of these, if necessary, in order to impart sharpness.

 U.S. Pat. No. 4,774,224 discloses that resin-coated paper having a surface roughness of 7.5 micron AA or less, especially resin-coated paper, has a surface of a base paper. There has been proposed a thermal transfer recording image-receiving element having, as a support, a polyethylene resin-coated paper coated with a polyethylene resin. Further, Japanese Patent Application Laid-Open No. 63-37979 discloses a technique relating to an ink jet recording sheet having a resin-coated paper as a support.

Furthermore, a technology for a photographic support in which the base paper surface opposite to the side on which the photographic layer is provided is coated with a resin composition containing a low-density polyethylene resin and a high-density polyethylene resin is proposed. Has been done. For example, Japanese Patent Publication No. 44-22904 discloses that the density is 0.915 to 0.926 g / cm ³ and the melting index is 2.9 to 16 g 0 minutes particular low density po re ethylene les down resin 1 5-6 5% by weight and density of 0. 9 6 0 ~0. 9 7 5 g / cm 3 der is, melt index of 5 to 1 8 A high-density coating consisting of 85 to 35% by weight of a specific high-density polyethylene resin that is 10 minutes long There is disclosure of a photographic support in which a base paper is coated with a polyethylene composition that does not generate any light. Japanese Patent Publication No. 48-9963 discloses that a base paper is coated with a resin composition consisting of low-density polyethylene resin: high-density polystyrene resin = 1: 1. There is a disclosure of a photographic support having good physical properties. Further, Japanese Patent Application Laid-Open No. 58-95732 discloses that the density is 0.945 g / cm ³ or more and the methylate index is 15 to 40 g / 1. 0 dense volume re ethylene les down RESIN 4 0-7 5 parts by weight and the density is minute 0. 9 ³ 0 g / cm 3 Ri der hereinafter main zone Les preparative Lee Nde' click Waals forces, '1 ~ Cutting properties and curl properties of base paper coated with a polyethylene resin composition consisting of 40 to 25 parts by weight of low-density polyethylene resin at 40 g / 10 minutes There is disclosure of a good photographic support.

 However, even if the resin composition comprising the low-density polyethylene resin and the high-density polyethylene resin disclosed in these prior arts is used, a resin-coated paper-type image using paper as a substrate can be used. Significant problems have been identified in the production of material supports. Further, the resin-coated paper-type imaging material support still has a serious problem in quality.

That is, first, the polyethylene resin-coated paper is prepared by using a melt extruder on a normally running base paper and using a melt extruder to melt the polyethylene resin composition from the slit die. The material is extruded into a film, cast and coated, pressed between a pressure roll and a cooling roll, and separated from the roll after cooling. Produced in a series of processes. However, when a resin composition composed of a conventionally known low-density polyethylene resin and a high-density polyethylene resin is used, a polymer called a cooling roll stain is placed on the cooling roll. There was a tendency for stains mainly composed of the ethylene resin composition or a modified product thereof to occur. Polyethylene-based resin-coated paper is produced by operating a melt extruder continuously for at least two to three days, usually one week, and sometimes for one month from the start of operation. The longer the period of continuous operation, the worse the cleaning and the tendency to accumulate more refrigerated roll dirt.

During the production of polyethylene-based resin-coated paper, if the cooling rolls start to become dirty, the separation of the polyethylene-based resin-coated paper from the cooling rolls deteriorates, and the cooling rolls and resin The adhesiveness between the base paper and the resin layer becomes uneven and weak because the adhesiveness between the base paper and the resin layer increases and the tendency for the resin layer to be removed on the cooling roll side increases. There is a problem that the resin and the resin layer are separated from each other so that the resin-coated paper for the support of the image material is completely unsuitable and has no commercial value. In addition, accumulated cooling roll dirt is wound up while being attached to the resin layer, and is transferred to the resin layer surface on which the image forming layer is provided, and appears. As for the resin-coated paper, there was a problem of causing fatal quality failure. Furthermore, the problem of the transfer of the cooling roll dirt is that the dirt is temporarily transferred to a roll of a laminator or a roll of an emulsion core for producing resin-coated paper. In some cases, it was a serious problem that it was re-transcribed and caused a quality failure. For this reason, it was necessary to take sufficient measures to prevent cooling roll contamination.

 Second, when a resin composition composed of a conventionally known low-density polyethylene resin and a high-density polyethylene resin is used, gel-like foreign matter tends to be generated on the surface of the coating resin. there were. This gel-like contaminant tends to be generated more often as the period of continuous operation becomes longer due to poor disposition.

If this gel-like foreign matter starts to be generated during the production of resin-coated paper, the resin in the coating will become thinner like streaks and sometimes crack the resin, resulting in a uniform resin-coated paper. A serious problem that could not be achieved. One side of the base paper is coated with a resin layer composed of a resin composition mainly composed of a polyolefin resin, and the other side of the base paper is mainly composed of a polyethylene resin. In a support for an image material covered with a resin layer composed of a resin composition having the following composition, the coating resin on the side opposite to the side on which the image forming layer is provided (hereinafter, simply abbreviated as the front side) (hereinafter, simply abbreviated as the back side) If a gel-like foreign substance is present in the layer, the appearance of the image material itself having the support is impaired, and its commercial value is lost. In particular, when a gel-like foreign matter is generated in the resin layer on the back side (hereinafter, simply referred to as a back resin layer), an image forming layer, particularly, is formed on the resin layer on the front side (hereinafter, simply referred to as a surface resin layer). When applying a silver halide photographic constituent layer, the coating is unevenly disturbed by the influence from the back side As a result, the image forming layer cannot be applied uniformly, which causes a fatal quality failure. For this reason, sufficient measures to prevent gel-like foreign matter had to be taken.

Therefore, the present inventors pursued the cause of the generation of the gel-like foreign matter. In the first place, when extruding and coating molten polyethylene resin on the base paper, it is performed at a temperature much higher than the melting point of the polyethylene resin. For example, the melting point of low-density polyethylene resin is around 105 to 110, and the melting point of high-density polyethylene resin is around 120 to 130 ° C. On the other hand, the melt extrusion temperature from the extrusion die needs to be around 300 ° C to perform thin film coating. Generally, in a polyethylene molecule, in addition to linear carbon as a polymer of ethylene monomer, unsaturated bonds such as carbon-carbon double bonds, and methyl It is known to contain side-chain carbons with groups or more carbon skeletons attached. For polyethylene, the temperature around 300 ° C is moderate from the viewpoint of processing suitability, but at the molecular level, it is in a range that promotes activation, and especially for long hours of operation. In such a case, radicals tend to be generated in the vicinity of unsaturated bonds and side-chain carbons in the molecule due to factors such as a change in the flow of the molten polyethylene resin, and the radicals undergo a chain reaction. As a result, the molten polyethylene resin causes a crosslinking reaction and is extruded, accumulates and stays inside the extruder, and sometimes becomes gel-like foreign matter when extruded together with the film. Thought to appear It has come.

 As a method to prevent the generation of such gel-like foreign matter, there is a method in which the extrusion process is performed at a lower temperature, but in this case, the adhesiveness between the polyethylene resin and the paper is reduced. Because of this, processing speeds are limited to maintain the required degree of adhesion, reducing productivity. In addition, although it is effective to disassemble and clean the extruder at short intervals, a reduction in productivity is inevitable. According to the study of the present inventors, addition of an antioxidant to a polyethylene resin composition is effective to some extent in preventing this gel-like foreign matter. However, it was necessary to add a large amount of an antioxidant, and in this case, there was a problem that the adhesion between the base paper and the resin layer was extremely insufficient. In particular, when produced under high-speed conditions in which the running speed of the base paper is 15 OmZ minutes or more, there was a problem that the adhesiveness between the base paper and the resin layer was further deteriorated.

Third, resin-coated paper as a support for imaging materials is required to have excellent smoothness on the surface of the resin surface.On the other hand, the texture, feel, and stiffness of the imaging material are low. For this reason, there is a demand for a support having a weight that meets the specifications of each user. The most effective way to improve the smoothness of resin-coated paper is to increase the coating amount of the surface resin layer, but reduce the basis weight of the base paper for the increase in the coating amount of the resin layer. If this is done, the above-mentioned properties such as texture, feel, and waist will be significantly degraded, so it is preferable to select a method that reduces the amount of coating on the back resin layer. No. However, in this case, there has been a problem that the image material using the resin-coated paper as a support is curled toward the image forming layer side and is extremely inconvenient to handle.

 For this reason, the resin composition for the back resin layer of the resin-coated paper-type image material support is mainly composed of a low-density polyethylene resin and a high-density polyethylene resin. By using the resin composition and increasing the content of the high-density polyethylene resin in the resin composition to increase the density of the back resin layer, the resin-coated paper can be used as a support. The curl properties of the image material are improved by flattening or curling the curl of the image material slightly on the back side. In this case, as the content of the high-density polyethylene resin in the resin composition increases, for example, the content becomes 60% by weight or more, In particular, when the content is 70% by weight or more, there arises a problem that the cutability of the resin-coated paper-type image material support coated with the resin composition or the image material having the image material support deteriorates. . That is, the support for the image material or the image material having the support for the image material may be a guillotine cutter, a precision print cutter, or a device such as a precision print cutter. One piece is cut to the desired size in the evening, but the image material support is not cut accurately, and whiskers are generated from the cut surface of the image material support, reducing the commercial value. The problem often occurred.

Furthermore, the smaller the amount of coating of the backing resin layer of the resin-coated paper type image material support, the better the adhesion between the base paper and the resin layer. There was also the problem of worsening. The problem of the adhesion between the base paper and the resin layer became more apparent as the running speed of the base paper increased.

 Accordingly, it is an object of the present invention to reduce the occurrence of dirt on the cooling roll during the production, and hence to avoid the problem attributed to the transfer of the dirt on the roll, and to provide an object opposite to the side on which the image forming layer is provided. No gel-like foreign matter is generated in the resin layer on the side, and the properties such as curl physical properties, cutting properties, and adhesion between the back resin layer and the base paper are good, and high-speed production is possible and stable production The base paper surface on the front side is coated with a resin composition containing a polyolefin resin as a main component, and the base paper surface on the back side is mainly made of a polyethylene resin. To provide a resin-coated paper-type image material support coated with a resin composition as described below. Other objects of the present invention will become clear from the description of the following specification.

 [Disclosure of the Invention]

 The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a specific high-density polystyrene and a specific medium-density polyethylene or low-density polystyrene are provided on one side of the base paper. It has been found that by coating with a resin layer comprising ethylene, a resin-coated paper suitable for use as a target support for an image material can be obtained.

That is, the present invention provides a resin-coated paper having a resin layer provided on one surface of a base paper, wherein the resin layer has a melt flow rate defined by JISK 670 of 10. Z l 0 min to 4 0. 0 g / \ 0 minutes, and dense Dopo Re ethylene les down resin 9 0 parts by weight to 6 5 parts by weight density of 0. 9 6 0 g / cm ³ or more, main Le walk B over rate 0 2 g Z l 0 min to 2 g Z l 0 min, density force

0.95 g / cm ³ or less, molecular weight of 500,000 or more, 10% by weight or more, and critical shear rate of 0.5 (1 second) or less Low density polyethylene resin or medium density It is composed of a polyethylene resin composition obtained by melt-mixing 10 to 35 parts by weight of a polyethylene resin, and has a critical shear rate of 10 (1). Seconds) It relates to resin-coated paper that is:

In addition, the present invention provides a resin having a methanol flow rate of 10 to 10 g / l 0 min to 40.0 g / l 0 min and a density of 0.96 g / cm ³ or more. 90 parts by weight to 65 parts by weight of high-density polyethylene resin, melt flow rate of 0.2 g Zl 0 min to 2 g Zl 0 min, density of 0.9 35 g Z cm ³ or less, low molecular weight polyethylene resin or medium density polyethylene with a ratio of molecular weight of 500,000 or more at 10% by weight or more and a critical shear rate of 0.5 (1 second) or less A method for producing a resin-coated paper comprising melt-mixing 10 parts by weight to 35 parts by weight of a lene resin, melt-extruding the polyethylene resin composition, and covering the base paper. The present invention also relates to a method for producing a resin-coated paper, wherein the melt-mixed resin composition has a critical shear rate of 10 (1 second) or less.

Further, according to the present invention, the melt flow rate of the resin layer provided on one side of the base paper is from 0 to 40 minutes, and the density is from 0.930 to 0.9. in 7 1 g / cm ^3, the critical shear rate 2 0 (1 second) This also relates to resin-coated paper that is less than or equal to.

[Brief description of drawings]

 Figure 1 is a chart showing the relationship between the shear stress and the first normal stress difference and the shear rate. The vertical axis shows the shear stress and the first normal stress difference, and the horizontal axis shows the shear rate. In the figure, a represents the shear stress, and b represents the first normal stress difference.

 [Best mode for carrying out the invention]

 Hereinafter, the present invention will be described in detail.

 In the present specification, the critical shear rate is defined as the difference between the shear stress measured at 240 ° C and the first normal stress using a cone-plate type rotary viscometer by the method described below. The shear rate at the point where

The high-density polyethylene resin used for the first resin layer in the resin-coated paper of the present invention is a methyl flow rate (hereinafter, referred to as MFR) specified in JISK670. Force l O. O g Z l 0 min to 40.0 g Z l 0 min, preferably 10.0 g / 10 min to 30.0 g Z l 0 min, density force Ku 0. 9 6 0 g / cm ³ or more, preferable to rather is more than ^{0. 9 6 2 g Z cm 3} . In the present invention, the critical shear rate of the high-density polyethylene is preferably about 10 to 100 (1 Z seconds), more preferably 20 to 80 (1 Z seconds). / Second). The high-density polyethylene resin (hereinafter referred to as HDPE) having the above-mentioned physical properties includes not only HDPE alone but also ethylene as the main component. Copolymers with lower-grade olefins such as TEN or And mixtures thereof.

 If the MFR force of the HDPE is lower than 10.0 g / 10 minutes, the adhesiveness between the base paper and the resin layer, moldability, etc. will deteriorate,

If it is higher than 40.0 g / 10 minutes, the mixing properties of the resin, the moldability and the like will be poor. On the other hand, when the density is lower than 0.96 g Z cm ³ , the secondary workability such as cutability deteriorates, and a favorable result cannot be obtained. As long as the MFR and density of the resin are within the above ranges, various MFRs, densities, molecular weights and molecular weight distributions can be used alone or as a mixture.

On the other hand, the low-density polyethylene resin (LDPE) or the medium-density polyethylene resin (MDPE) used for the resin layer has an MFR of 0.2 g Z 10 min. ~ 2 g / l 0 min, Ri preferred and rather is 0. 2 g Z l 0 min or 1. 0 g / 1 range der less than 0 minutes, density 0. 9 ³ 5 g / cm 3 or less, preferred Or less than 0.930 g / cm ³ , the proportion of a molecular weight of 500,000 or more is 10% by weight or more, preferably 12% by weight or more, and the critical shear rate is 0.9%. It is less than 5 (1 Z seconds), preferably less than 0.4 (1 Z seconds).

If the MFR of the LDPE is lower than 0.2 g Zl0 min, the resin mixability, adhesion between the base paper and the resin layer, moldability, etc., will deteriorate, and the LDFR MFR will be lower than 2 g / 10 min. If it is too high, the formability will deteriorate. On the other hand, if the density is higher than 0.935 g Zcm ³ , the adhesion between the base paper and the resin layer, the formability and the like will be poor, and no favorable results will be obtained. On the other hand, if the proportion of the resin having a molecular weight of 500,000 or more is less than 10% by weight, moldability, especially neck-in is large. I don't like it. The molecular weight was measured using Waters' 150-C (column: GMH-XLHT 8 mm 0 X 30 cm X 3 from Tohso-Ichi, solvent: 1, 2, 4-Tri- GPC method using a closed vent benzene, temperature: 135 ° C, flow rate: 1 mlZ min).

 Also, the critical shear rate of L DPE or M DPE is 0.5

(1 Z seconds) or less, and if it is larger than this, problems such as moldability and gelation of the resin layer occur.

 Fig. 1 is a chart showing the relationship between the shear stress and the first normal stress difference, and the shear rate. In Fig. 1, the vertical axis shows the shear stress and the first normal stress difference, and the horizontal axis shows Indicates the shear rate. The line a in Fig. 1 shows the shear stress, and the line b shows the first normal I difference.

 The measurement of the critical shear rate in the present invention is performed by using a cone-plate type rotary viscometer (Rheometrics meter manufactured by Rheometrics Co., Ltd.). The diameter of the cone plate was 25 mm, the angle was 0.1 rad, and the temperature was 240 ° C. In Fig. 1, the shear stress and the first normal stress difference were equal. It is the shear rate at the point where the curve changes (the intersection of line a and line b). The shear stress and the first normal stress difference can be obtained from the following equations.c

 Shear stress = (viscosity) X (shear rate)

First normal stress difference = (First normal stress difference coefficient) X (Shear rate) ²

The resin layer in the resin-coated paper of the present invention has 90 weights. Parts by weight to 65 parts by weight of the HDPE having the above-mentioned physical properties, and 10 parts by weight to 35 parts by weight of an LDPE or MDPE having the above-mentioned physical properties, which is previously melt-mixed to prepare a polyethylene resin. A compound resin composed of a composition is used. It is necessary that the critical shear rate be 10 (1 second) or less, and a material having a critical shear rate of 8 (1 second) or less is particularly preferable. If the critical shear rate is higher than 10 (1 nosec), gel is likely to be generated, which is not preferable. The composition obtained by melt-mixing the HDPE and the LDPE or the MDPE has a MFR content of preferably 1.4 to 36 g ZL O, more preferably 4 g. . 0~ 1 5 g Z l at O min Ah is, density 0. 9 3 2~ 0. 9 7 0 g / cm 3 in which this and is favored arbitrary.

 It is considered that the suppression of gel formation according to the present invention is due to the viscoelastic properties of the resin at a high resin temperature during melt extrusion coating, and the above critical shear rate of 10 (1 Z seconds) or less It is considered that the change in the properties of the resin from viscous to elastic at the same time reduces the chance of gelation and suppresses the gel by crushing and kneading the gel.

As a method of melt-mixing the above ratio of HDPE and LDPE or MDPE, a simple melt-mixing method, a multi-stage melt-mixing method, or the like can be used. For example, a Banbury mixer, a pressure kneader, a heating roll kneader, an extruder, a twin screw extruder and the like are used. HDPE and LDPE or MDPE should not be melt-mixed beforehand, but should be extruded using a melt-coating extruder in a dry-mixed state. In this case, the adhesiveness between the base paper and the resin layer, the mixing property of the resin, the moldability, and the like are deteriorated.

 As long as the effects of the present invention are not impaired, the polyethylene-based resin composition used in the resin layer may contain an ultraviolet ray inhibitor, a heat stabilizer, an antistatic agent, an antioxidant, a light stabilizer, a lubricant, a nucleus. Various additives such as a coloring agent and a coloring agent can be appropriately added. These additives are added in advance to the HDPE or LDPE or MDPE to be used, added at the time of melt mixing, or prepared in advance in a so-called masterbatch which is added to these resins at a high concentration. This masterbatch may be added to the resin during melt extrusion coating.

 Examples of the base paper used in the present invention include natural pulp paper mainly containing natural pulp, mixed paper made of natural pulp and synthetic fiber, synthetic pulp, synthetic fiber, or synthetic resin film. Any of synthetic paper consisting of In addition, the base paper can contain various additives such as a size agent, a paper strength agent, a base, a fixing agent, a pH adjuster, a coloring agent, and a fluorescent whitening agent.

In order to produce the resin-coated paper of the present invention, the above-mentioned polyethylene-based resin composition is cast on a running base paper from a slit die into a film by using a melt extruder. The so-called melt extrusion coating method for coating is adopted. The melt extrusion temperature is usually 280 ° C or more preferably 340 ° C. Before coating the polyethylene resin composition on the base paper, Activation treatment such as corona discharge treatment and flame treatment This is preferred. Although the thickness of the resin layer is not particularly limited, it is generally applied to a thickness of not more than 5 micron or about 50 micron.

Furthermore, the present inventors have conducted intensive studies, and as a result, it has been found that, on both sides of the base paper, a resin-coated paper coated with a resin layer composed of a resin composition containing a polyethylenic resin as a main component has an image The resin layer on the side where the forming layer is provided, that is, the resin coating amount in the second resin layer and the resin layer on the opposite side to the side where the image forming layer is provided, that is, the resin coating amount in the first resin layer if the difference is on 3 g Z m ² or more, and this the objects can be effectively attained Ri good of the present invention has been found. The first resin layer is a compound resin prepared by previously melting and mixing a high-density polyethylene resin and a low-density polystyrene resin or a medium-density polyethylene resin. When the resin composition is a resin composition and the critical shear rate of the compound resin is 10 (1 / sec) or less, the object of the present invention can be achieved even more effectively. found. The low-density polyethylene resin or the medium-density polyethylene resin may have a mole fraction of 0.2 g Zl 0 min or more and 1 g / 10 min. It has been found that the object of the present invention can be more remarkably achieved by constituting the compound resin with less than the above.

As the low-density polyethylene resin or the medium-density polyethylene resin of the first resin layer, for example, a high-pressure method low-density polyethylene resin (autocrap method low-density polystyrene resin) is used. Ethylene resin, tuber method low density polyethylene resin), linear low density Polyethylene resin, medium-density polyethylene resin, copolymer of ethylene with propylene, butylene and other olefins, carboxy-modified polyethylene Various materials such as resins and mixtures thereof can be used.

 The ratio, density, MFR, and critical shear rate of the low-density or medium-density and high-density polyethylene resins in the first resin layer are determined by the support for the imaging material. Mixing properties of resin at the time of manufacturing, molding processability, effect of preventing gel-like foreign matter, adhesion between base paper of image material support and resin composition layer, curl physical properties, cutting properties, touch feeling, waist etc. The performance as a support for an image material and the like were determined from comprehensive observations as a result of trial and error experiments, and the present invention has been achieved. In particular, the amount of high-density polyethylene resin used in a resin composition consisting of high-density polyethylene resin and low- or medium-density polyethylene resin is 90%. It is in the range of from 85 to 70 parts by weight, preferably from 85 to 70 parts by weight, and more preferably from 80 to 70 parts by weight. If the amount of the resin used is less than 65 parts by weight, the curl physical properties, cutting properties, stiffness, etc. of the support for the image material deteriorate, which is a problem. The problem is that the mixing properties, moldability, and the adhesiveness between the base paper and the resin layer are deteriorated.

The MFR of the high-density polyethylene resin of the first resin layer is in the range of 1 Og Zl 0 min to 40 g / I 0 min, preferably 10 g Z l 0 min to 30 g Z l O min range It is. If the MFR of the resin is lower than 10 g Z 10 min, the adhesion between the base paper and the resin layer, the high-speed processability, etc. are deteriorated, which is a problem, and is higher than 40 g / 10 min. It is a problem that the mixing property of the resin and the resin, the moldability and the like become poor, and the curl properties tend to be poor. The density of the high-density polyethylene resin is 0.96 g / cm ³ or more, but if the density is less than 0.96 g / cm ³ , der and the like evil rather connexion problem waist is, der 0. 9 6 2 g / cm ³ or more to rather than the preferred ο

On the other hand, the MFR of the low-density polyethylene resin or the medium-density polyethylene resin of the first resin layer is in the range of 0.2 g Zl 0 min to 2 g Z l 0 min. If the value is lower than 0.2 g Zl 0 min, the mixing properties of the resin, the adhesion between the base paper and the resin layer, and the high-speed processability are deteriorated, which is a problem, and the value is higher than 2 g 10 min. In addition, the molding processability is deteriorated, and the curl physical properties tend to be poor, which is a problem, and is preferably in the range of 0.2 g Z10 minutes to 1 g Z10 minutes. . The low-density or medium-density polyethylene resin has a density of 0.935 g / cm ³ or less, and a density of 0.935 g. If it is higher than / cm ³ , the molding processability of the resin composition and the adhesiveness between the base paper and the resin layer are deteriorated, which is a problem, and preferably 0.99 g / cm ³ or less. is there. The fraction of the resin having a molecular weight of 500,000 or more is 10% by weight or more, and preferably 12% by weight or more. When the fraction of the resin having a molecular weight of 500,000 or more is less than 10% by weight, moldability, especially neck-in is large. That is a problem.

 As described above, it is preferable that the first resin layer is formed using a compound resin prepared by melting and mixing in advance. A simple method for preparing a compound resin by previously melting and mixing a low-density or medium-density polyethylene resin and a high-density polystyrene resin is as follows. A melt mixing method, a multi-stage melt mixing method, or the like can be used. For example, using an extruder, a twin-screw extruder, a heating roll kneader, a kneader mixer, a pressure kneader, etc., a predetermined amount of low-density or medium-density polyethylen It is advantageous to use a method in which the resin is mixed with various additives such as an antioxidant and a lubricant, if necessary, and then melted and mixed, and then the mixture is pelletized. Used. If the polyethylene resin is directly added to the melt extruder in the state of simple mixing without being used as the compound resin, and then melt-extruded and coated, The problem is that the adhesiveness between the base paper and the resin layer, the mixing property of the resin, the moldability and the like are deteriorated.

The critical shear rate of the above-mentioned compound resin is set to 10 (1 second) or less, especially in order to prevent gel-like foreign substances that are generated over time during extrusion and melt coating. Or less, preferably 8 seconds) or less. If the critical shear rate is higher than 10 (1 Z second), gel-like foreign matter is generated, which is a problem. The effect of preventing the generation of gel-like foreign matter according to the present invention is attributed to the viscoelastic properties of the resin at a high resin temperature during melt extrusion coating. It is considered that the property of the resin changed from viscous to elastic at the critical shear rate, which was attributed to a decrease in the gelation opportunity, gel grinding and improved kneading, etc. .

As described above, the surface of the resin-coated paper of the present invention on the side on which the image forming layer is provided is preferably coated with a resin composition containing a polyethylene resin as a main component. Examples of such polyethylene resins include low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, and linear low-density polyethylene resin. Various resins such as styrene resin, copolymers of ethylene and propylene, butylene, etc., and carboxy-modified polyethylene resin, and mixtures thereof. Can be used. Further, various densities of, MFR, molecular weight, but you can use those molecular weight distribution, typically, density ^{0. 9 1 g / cm 3} ~ 0. 9 7 g / cm 3 range, MFR 1 g / 1 0 min Those having a molecular weight of 20,000 to 250,000 can be advantageously used singly or as a mixture.

The difference between the coating amount of the resin in the second coating amount of the resin in the resin layer and the first resin layer is, 3 g Zm ² or more is preferred rather, 5 g Z m ² or rather to preferred Ri good, 7 g Zm ² or more is particularly preferred. If the difference between the resin coating amounts on the front and back sides is less than 3 g Zm ² , the image material using the resin-coated paper as a support is curled on the opposite side of the image forming layer, and the handling is remarkable. This is a problem because it is inconvenient, and furthermore, the cutting property of the support for the image material or the image material having the support for the image material is deteriorated. That is, the image material support or the image material The image material having a support for printing is cut to a desired size by a cutter such as a guillotine cutter, a precision print cutter, or a precision print cutter. In many cases, the image material support is not cut accurately, and a whisker-like object is generated from the cut surface of the image material support, thereby deteriorating the commercial value. In the case of the image material having the body or the support for the image material, the cut surface is good.

As described above, the support for the image material is cast into a film form from its slit die using a melt extruder of a polyethylene resin composition onto a running base paper. It is preferred to be manufactured by a so-called melt-extrusion coating method of coating by coating. At that time, the temperature of the molten film is more preferably from 280 ° C to 340 ° C. As the slit dies, T-type dies, L-type dies, and flat type dies are preferred, and the slit opening diameter is 0.1 mm to 2 mm. It is desirable that Before coating the resin composition on the base paper, the base paper is preferably subjected to an activation treatment such as a corona discharge treatment or a flame treatment. Further, as described in Japanese Patent Publication No. Sho 61-422254, a resin layer is coated on a running base paper after spraying an ozone-containing gas onto a molten resin composition in contact with the base paper. May be. Further, the first and second resin layers are sequentially and preferably continuously extruded and coated, that is, the base paper is coated with a so-called tandem extrusion coating method. Preferred and necessary According to the requirements, the first or second resin layer may be formed by a multilayer extrusion coating method in which each of the first and second resin layers has a multilayer structure of two or more layers. The surface of the second resin layer of the support for image materials is processed into a glossy surface, a slightly rough surface described in Japanese Patent Publication No. 62-19732, a matte surface or a silk surface. The first resin layer is usually preferably processed to a matte surface. The thickness of the second resin layer is preferably 9 μm to 100 μm, more preferably 12 μm to 55 μm. is there. The thickness of the first resin layer is preferably from 5 m to 95 m, but more preferably from 8 m to 50 m.

Various additives can be contained in the first and second resin layers of the support for image materials. Japanese Patent Publication No. 60-33430, Japanese Patent Publication No. 63-116 1655, Japanese Patent Publication No. 1-38 291, Japanese Patent Publication No. 1-38282, Japanese Patent Publication No. Hei 1-1 White pigments such as titanium oxide, zinc oxide, zinc, and calcium carbonate, stearic acid amide, and arachidic acid acid described in each of the publications such as No. 2525 Fatty acid amides, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, etc. Fatty acid metal salts such as zinc lumitinate, zinc myristate, and calcium palmitate; and the hindered phenols described in JP-A No. 11052/45. , Hindered amine, phosphorus-based, sulfur-based antioxidants, and cobalt-based blue pigments such as cobalt blue, ultramarine blue, celium blue, phthalocyanine blue, etc. dye, Magenta-colored pigments and dyes such as rut-no-rayette, fast-pawlette, mangan-no-rayet, etc., JP-A-2-254440 Various additives such as a fluorescent whitening agent and an ultraviolet absorber described in the gazette can be appropriately combined and contained. These additives are resin batches or composites. It is preferable to include it as a solvent. In particular, as a method of incorporating these additives into the composite resin composition for the first resin layer used in the practice of the present invention, a high-density polyethylene resin and a high-density polyethylene resin are used. Pre-added to low-density polyethylene resin or medium-density polyethylene resin, added at the time of compound resin preparation, or a master batch added to the resin at a high concentration Alternatively, the master batch may be melt-extruded and added to the resin at the time of coating.

The base paper is preferably a natural pulp paper mainly composed of natural pulp (hereinafter, the base paper mainly composed of natural pulp is simply referred to as base paper). Also, a mixed paper made of natural pulp and synthetic pulp or synthetic fiber, or a so-called synthetic paper made of synthetic pulp, synthetic fiber or synthetic resin film may be used. The thickness of the base paper is not particularly limited, but preferably has a basis weight of 40 g / m ² to 250 g / m.

The pulp constituting the base paper that is preferably used is described in JP-A-58-37642, JP-A-60-67940, JP-A-60-696. No. 49, Japanese Patent Application Laid-Open No. 61-35 4 4 2 It is advantageous to use appropriately selected natural pulp as described in each gazette. Natural pulp is bleached in the usual bleaching process of chlorine, hypozincate, chlorine dioxide bleaching, alkali extraction or alkaline treatment, and oxidative bleaching with hydrogen peroxide, oxygen, etc. as necessary. Wood pulp of softwood pulp, hardwood pulp, softwood pulp mixed pulp, etc., which has been subjected to a treatment such as kraft krupp, sanoleite, etc. ^You can use various kinds of materials such as ⁰ rupe and soda pulp. Various additives can be included in the base paper during preparation of the stock slurry. Examples of the size agent include fatty acid metal salts and / or fatty acids, alkyl ketene dimer emulsions described in JP-B-62-73534, or epoxy-modified higher fatty acid amides, alkenyls and alkyl succinic acids. Anionic, cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, plant, etc. as dry paper strength enhancers such as anhydride emulsions and rosin derivatives As a wet paper strength enhancer such as garment mannan, polyamine polyamide midechlorohydrin resin, etc. Water, water-soluble aluminum salts such as aluminum chloride and bansulfate, etc., as caustic soda, sodium hydroxide, calcium hydroxide, titanium oxide, etc. Soda carbonate, sulfuric acid, etc. -2 0 4 2 5 1 and Japanese Patent Application Laid-Open No. 1-2666537, etc., contain color pigments, coloring dyes, fluorescent brighteners, etc. as appropriate in combination. Advantageously.

 In the base paper, various water-soluble polymers, antistatic agents and additives can be incorporated by spraying or tab size press. Examples of the water-soluble polymer include starch-based polymers, polyvinyl-alcohol-based polymers, gelatin-based polymers, and polymers described in Japanese Patent Application Laid-Open No. 1266663/1999. Examples of antistatic agents such as lithium amide polymers and cellulose polymers, such as alkali metal salts such as sodium chloride and potassium chloride, calcium chloride, barium chloride, etc. Emulsion, latex, etc., such as alkaline earth metal salts, colloidal metal oxides such as colloidal silica, and organic antistatic agents such as polystyrene sulfonate Classes include ethylene or vinyl acetate copolymer emulsions or latexes, petroleum resin emulsions, and pigments such as clay, kaolin, talc, barium sulfate, and the like. Hydrochloric acid, lithium, etc. as pH regulators such as titanium oxide It is advantageous to incorporate an appropriate combination of additives such as the above-mentioned coloring pigments, coloring dyes, and optical brighteners, such as acid, cunic acid, and caustic soda.

As the base paper, those having a smooth surface with a Beck smoothness of 100 seconds or more specified by JISP 8119 are preferable, and those having a smooth surface of 200 seconds or more are preferable. More preferred. As a method for producing a base paper having a Beck smoothness of 100 seconds or more, generally, a large amount of hardwood pulp that is short-textile and easily smooth is used, and a long beater is used by a beater. The woven fiber becomes Beat it so that it is less. Specifically, the pulp is beaten so that the weave length of the pulp after beaten becomes 42-45% for the mesh residue and 200-350 CSF for freeness. I prefer to do it. Next, regarding the stock slurries to which the internal additives have been added, JP-A-58-37642, JP-A-61-2600, JP-A-61-2. By adopting an appropriate papermaking method as described in each of the publications such as No. 8 4 7 6 2, uniform formation can be achieved with commonly used paper machines such as fourdrinier and round net paper machines. The paper is formed so that it can be obtained, and after the paper formation, it is subjected to a calendar treatment using a machine calendar, a super calendar, a heat calendar, etc., and the Beck smoothness is 100 seconds or more. Base paper can be manufactured.

After an activation treatment such as a corona discharge treatment or a flame treatment is performed on the second resin layer, JP-A-6-84643, JP-A-Hei 1992740, JP-A No. An undercoat layer as described or exemplified in each of the official gazettes such as Kaihei 1-10102551 and JP-A-11-66035 can be applied. Further, on the first resin layer of the resin-coated paper according to the present invention, after performing an activation treatment such as a corona discharge treatment and a flame treatment, various back coat layers are coated for antistatic and the like. Can be set up. Also, in the knock coat layer, Japanese Patent Publication No. 52-180,200, Japanese Patent Publication No. 57-950, Japanese Patent Publication No. 57-539940, Japanese Patent Publication No. Organic antistatic agents, organic compounds described in JP-A Nos. 8 — 569859, JP-A-59-2194849, JP-A-58-184414, etc. Antistatic agent, hydrophilic binder, glass Textiles, curing agents, pigments, surfactants, etc. can be included in appropriate combinations.

The support for image materials is coated with various photographic constituent layers and is used for color photographic paper, black and white photographic paper, typesetting photographic paper, copy photographic paper, reversal photographic material, silver salt diffusion transfer method. It can be used for various purposes such as negative, positive, and printing materials. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be provided. C. A multilayer silver halide color photographic layer can be provided by incorporating a color coupler into the π-silver halide photographic emulsion layer. Further, a photographic component layer for silver salt diffusion transfer method can be provided. As binders for these photographic constituent layers, in addition to ordinary gelatin, hydrophilic polymers such as polyvinylpyrrolidone, polyvinyl alcohol, and sulfate compounds of polysaccharides are used. Substances can be used. In addition, the above-mentioned photographic constituent layer can contain various additives. For example, sensitizing dyes such as cyanine dyes and merosianin dyes; chemical sensitizers such as water-soluble gold compounds and zeolite compounds; Are hardeners such as hydroxytriazole azopyrimidine compounds and mercapto monoheterocyclic compounds, and formalin, vinyl sulfone compounds and aziridines as hardeners. Compounds and other coating aids such as alkylbenzenesulfonates and sulfosuccinates, etc., and anti-fouling agents such as dialkylhydroquinone compounds, and other fluorescent brightening agents Agent, sharpness improving dye, antistatic agent, pH A water-soluble iridium, a water-soluble rhodium compound, and the like can be appropriately combined during the formation and dispersion of a silver halide and a preparation agent, a fogging agent, and the like.

 The photographic material according to the present invention may be used in accordance with the photographic material, such as exposure, development, stop, and fixation as described in “Photosensitive Material and Handling Method” (Kyoritsu Shuppan, Goro Miyamoto, Photo Technology Course 2). , Bleaching, stable processing, etc. Further, the multi-layer silver halide color photographic material may be processed with a developing solution containing a development accelerator such as benzyl alcohol, a tallium salt, or phendon. Alternatively, it can be processed with a developer substantially free of benzyl alcohol.

The support for image materials can be used as a support for various thermal transfer recording image-receiving materials, provided with various thermal transfer recording image-receiving layers. Synthetic resins used for the thermal transfer recording image receiving layer include polyester resin, polyacrylate resin, polycarbonate resin, vinyl acetate resin, polyvinyl butyrate. Resins having ester bond such as resin, polystyrene resin, vinyl toluene clear resin, resin having urethane bond such as polyurethane resin, poly Resins with amide bonds, such as amide resins, resins with urea bonds, such as urea resins, other polylactic acid resins, styrene resins, polyvinyl chloride resins, and vinyl chloride-acetic acid Bull copolymer resins, polyacrylonitrile resins, and the like. In addition to these resins, mixtures or copolymers thereof can also be used. In the thermal transfer recording image receiving layer, a releasing agent, a pigment, and the like may be added in addition to the synthetic resin. Examples of the release agent include solid waxes such as polyethylene wax, amide wax, teflon, ^zero powder, fluorine-based resin, and resin. Ester surfactants, silicone oils, and the like. Of these release agents, silicone oil is the most preferred. As the above silicone oil, an oily substance can be used, but a cured type is preferred. Examples of the curable silicone oil include a reaction-curable silicone, a light-curable silicone, and a catalyst-curable silicone oil. A reaction-curable silicone oil is particularly preferable. Examples of the reaction-curable silicone oil include amino-modified silicone oil, epoxy-modified silicone oil, and the like. The addition amount of the reactive silicone oil is preferably 0.1 to 20 wt% in the image receiving layer. As the above-mentioned pigment, extenders such as silica, calcium carbonate, titanium oxide, and zinc oxide are preferable. The thickness of the image receiving layer is preferably 0.5 to 20 μm, and more preferably 2 to 10 / m.

The support for an image material can be used as a support for various ink jet recording materials provided with various ink receiving layers. Various binders can be contained in the ink receiving layer for the purpose of improving the dryness of the ink and the sharpness of the image. Specific examples of such binders include lime-treated gelatin, acid-treated gelatin, enzyme-treated gelatin, and gelatin derivatives, such as phthalic acid, maleic acid, and fumaric acid. Reacts with the dibasic acid anhydride Various types of gelatin, such as gelatin, etc., ordinary polyvinyl alcohol of various degrees of genation, carboxyl-modified, cation-modified and amphoteric polyvinyl alcohol and derivatives thereof, oxidation Starches such as starch, cationized starch, and etherified starch; cellulose derivatives such as carboxymethyl cellulose; hydroxyl derivatives; polyvinyl derivatives; Pyrrolidone, Polyvinyl pyridinolamide, Polyacrylinoleic acid leader, Acrylinoleic acid Methacrylic acid copolymer salt, Polyethylene Alcohol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether, maleic anhydride copolymer, styrene / maleic anhydride copolymer and Salt, polyethylenim etc. Conjugated gen-based copolymers such as synthetic polymers, styrene / butane diene copolymers, methyl methacrylate / butadiene copolymers Vinyl acetate, vinyl acetate / maleic acid ester copolymer, vinyl acetate / acrylic acid ester copolymer, ethylene ■ Vinyl acetate copolymers such as vinyl acetate copolymer Tex, acrylate polymer, methyl acrylate polymer, ethylene acrylate copolymer, styrene acrylate Acrylic polymers such as copolymers, latexes of copolymers, vinylidene chloride copolymer latexes, or various types of these polymers Functional group-modified polymer latex and monomer with functional group-containing monomer such as carbosyl group Butter, aqueous adhesives and Po Li methylation meth click Li rate of the thermosetting synthetic resin such as urea resin, Po Re c letterhead down resin, Synthetic resin-based adhesives such as unsaturated polyester resin, vinyl chloride 'vinyl acetate copolymer, polyvinyl butyral, and alkyd resin, Japanese Patent Publication No. 3-24906, 3-2 8 1 3 8 3 No. 4, Japanese Patent Application No. 4-2 0 7 2 5 List of inorganic binders such as alumina and silica sol described in each official publication such as No. 4 These can be used alone or in combination.

The ink receiving layer of the ink jet recording material may contain various additives in addition to the binder. For example, as the surfactant, an anionic surfactant such as a long-chain alkylbenzenesulfonate, a long-chain or branched-chain alkylsulfonate ester salt, a long-chain, preferably Nonionic surfactants such as polyalkylene oxide ethers of phenols containing branched alkyl groups, and polyalkylene oxide ethers of long-chain alkyl alcohols; 7-amino propyl triethoxysilane, such as the fluorinated surfactants described in U.S. Pat. No. 3,003, U.S. Pat. No. 3,589,906, etc. — S (Aminoethyl) α-Aminoprovir Trimethoxysilane Active halogen as a silane coupling agent such as silane and a hardener for polymers. Gen compounds, vinyl sulfone compounds, As hardening agents and preservatives such as diene compounds, epoxy compounds, acryloyl compounds, and isocarbonate compounds, the compounds described in JP-A-1-125551 are disclosed. P—Hydroxybenzoic acid ester compound, Benzoisotia zolone compound, Isochi Azolone compounds, coloring pigments, coloring dyes, fluorescent brighteners described in JP-A-63-20451, JP-A-1266663, etc. Hydroxymethansulfonate soda as a yellowing inhibitor, P-tonolene sonophosphate sodium, etc., etc. As an antioxidant such as a benzotriazole compound having a monoalkyl group at the 2-position, a polyhydric acid described in Japanese Patent Application Laid-Open No. H11-25445 (1) As a lead brushing agent such as a phenolic compound, fine particles of organic or inorganic particles such as starch granules, barium sulfate, and silicon dioxide with a particle size of 0.2 / m to 5 / m, The organopolysiloxane compound described in Japanese Patent Publication No. 4-13337, as a pH regulator, sodium hydroxide, sodium carbonate, sulfuric acid, hydrochloric acid, phosphoric acid, Etc. E phosphate, O Kuchiruaruko Lumpur, Ru can and this that allowed to contain Te appropriate combination shea re co down based defoaming agents which various additives.

Further, the present inventors have found that, in producing a polyethylene resin-coated paper by the extrusion melt coating method, the resin layer can be formed without lowering the productivity. Extensive studies were conducted to provide an extrusion melt-coating method that has good workability and good adhesion between the resin layer and the base paper and that prevents gel formation in the resin layer. In the method of producing resin-coated paper by extrusion-coating a resin, when a polyethylene resin is melt-extruded from an extruder, the screw speed of the extruder is set to a critical speed (Nc The above-mentioned object is achieved by melt-extruding the polyethylene resin at the above rotation speed. There was found.

 The above critical rotation speed (Nc) is determined by the following method.

 6 0HCS R

 N c = (1)

 πD

 Where N c is the critical screw speed (rpm)

 CSR: Critical shear rate of resin (1 second)

 H: Depth of screw screw groove at lower part of hopper (cm) D: Barrel inner diameter (cm) The screw rotation speed of the extruder used in the present invention is a commercially available screw speed installed in the extruder. It can be easily measured with a tachometer.

 If the rotational speed of the screw of the extruder is not higher than the critical rotational speed according to the above equation (1), it is not preferable since gel generation in the resin layer is insufficiently prevented.

 In practice, it is preferable that the critical rotation speed is small in order to widen the operating range during extrusion melt coating. As a method for reducing the critical rotation speed, a method using a resin having a critical shear rate as low as possible within the range permitted by the present invention can be used alone or in combination of two or more. .

In order to extrude and coat the polyethylene resin melt-extruded from the die of the extruder on the base paper, the base paper may be directly extrusion-coated, or the base paper and the polyethylene resin may be extruded. Known surface activities such as corona discharge treatment, flame treatment, anchor coat treatment, etc. are applied to the adhesive surface of the base paper in advance to increase the adhesive strength with the resin. Extrusion coating may be performed after the oxidizing treatment.

 The extrusion coating can be carried out by using a known method and apparatus. For example, a polyethylene resin is extruded from a die of an extruder at a resin temperature of 280 to 34 ° C. The molten thin film is guided to a pressure roll, and the base paper, the pressure roll, and the cooling roll whose adhesive surface is untreated or subjected to the above-described surface activation treatment and also guided to the pressure roll. This is done by extrusion coating through a varnish.

 The thickness of the polyethylene resin layer is not particularly limited, but is usually in the range of about 5 to 50.

 As the polyethylene resin used as the resin layer, high-density polyethylene, low-density polyethylene or medium-density polyethylene is used.

 For the production of base paper preferably used in the present invention, commonly used papermaking paper such as a fourdrinier paper machine and a round net paper machine can be used.

 Further, as a result of intensive studies by the present inventors, it has been found that the substrate can achieve the object of the present invention particularly effectively when the film thickness direction non-uniformity index R py defined below is 140 mV or less. found.

The film thickness unevenness index R py referred to in this specification is defined as follows. In other words, a sample is moved between two spherical stylus-electron micrometer using a film thickness measuring device that measures the thickness variation of the sample as an electric signal via an electronic micrometer. Scanning at a constant speed of 1.5 m in the papermaking direction of the sample after adjusting the zero point under the condition that the sensitivity range of the meter is 15 m Z soil 3 V In this way, the thickness variation of the sample in the papermaking direction is measured, and the obtained measurement signal value is subjected to a fast Fourier transform by using a FFT analyzer and a time window in a time window. Calculate the power spectrum (unit: mV 2) by adding and averaging the eight integrations, sum the power values in the frequency range of 2 Hz to 25 Hz, and multiply by 23. Is defined as the film thickness unevenness index Rpy (unit: raV).

Specifically, it is obtained as follows. The sample is run between two spherical styluses with a measuring pressure of about 30 g / stroke with a diameter of about 5 mm, and the variation in the thickness of the sample is measured via an electronic micrometer. Using a film thickness measuring device manufactured by Anritsu Co., Ltd. to measure as an electric signal, the sensitivity range of the electronic micrometer is ± 15 m / ± 3 V Under the condition, after the zero point preparation, the thickness variation of the sample in the papermaking direction was measured by scanning at a constant speed of 1.5 mZ in the papermaking direction of the sample, and the obtained measurement value was measured by Ono Sokki ( Co., Ltd. FFT Analyzer CF-300 type machine (input signal AC ± 10 mV, sampling 512 points), the time window is set to the hanging window, and the frequency range is set. Fast Fourier transform (FFT) with 50 Hz processing conditions, and linear average scale based on the averaging of 128 integrations. Find the power vector (unit: mV), multiply the value obtained by summing the squares of the power values on the linear scale in the frequency range of 2 Hz to 25 Hz, multiply by 2/3, and multiply by 1 2 You can ask for it by doing. Other frequency analysis conditions Is performed under the initial setting conditions of the CF-300 model.

 An object of the present invention is to use, as a base paper, a resin-coated paper having a thickness unevenness index Rpy of 140 mV or less in the papermaking direction as defined in the present specification, and specifying the coating resin. It has been found that a synergistic effect can be achieved by using a resin composition containing a polyethylene-based compound resin as a main component. In particular, according to the present invention, the cutting property of the resin-coated paper-type image material support is synergistically improved, and the cut surface is extremely good in the image material support or the image material having the support according to the present invention. is there. Further, the object of the present invention is remarkably achieved by using, as a base paper, a base paper having a film thickness nonuniformity index Rpy of 135 mV or less in the papermaking direction. I found it. Further, an object of the present invention is to provide a low-density polystyrene resin or a medium-density polyethylene resin in a polyethylene-based compound resin, It was found that remarkably achieved by using a material having a roll rate of 0.2 g Zl0 min or more and less than 1 g / 10 min, and reached the present invention. It is.

As the base paper mainly composed of natural pulp used in the present invention, a film thickness unevenness index Rpy in the papermaking direction as defined in this specification (the term film thickness unevenness index Rpy in the papermaking direction is simply referred to as The thickness unevenness index Rpy is a value of 140 mV or less, but a value of 135 mV or less is preferable, and a value of 130 mV or less is more preferable. The base paper having a film thickness non-uniformity index Rpy of 140 mV or less is specifically manufactured by using the following method. The present inventors have studied that it can be obtained by using preferably two or more of the following methods, more preferably three or more methods, and most preferably four or more methods. O became clear

 (1) As the natural pulp to be used, hardwood pulp that is short fiber and easily smooth is used in many cases. Specifically, for example, hardwood pulp described in Japanese Patent Application Laid-Open No. Sho 60-69649 is used in an amount of 60% by weight or more, preferably 75% by weight or more.

 (2) The pulp is beaten by a beater so that the long fiber content is as small as possible. Specifically, for example, the beating of pulp is based on the length-weighted average fiber length measured in accordance with JAPAN TAPPI Paper and Pulp Test Method No. 52-89 “Weaving length test method for paper and pulp”. 0.4 to 0.75 mm. Preferably 0.45 to 0.7 mra, more preferably 0.45 to 0.65 mm, and the cumulative weight of fiber length 1 mm or less is 7 At least 0%, so that the freeness is between 200 and 330 CSF.

(3) Use a papermaking method appropriate for the stock slurry to which the internal chemicals have been added, and make a fourdrinier paper machine to produce a base paper so that a uniform formation can be obtained. Specifically, for example, i) Give a stock slurry an appropriate evening bure. ϋ) Use a fourdrinier paper machine having an appropriate upper dewatering mechanism as described in JP-A-6-12847472. Ii) The press of the wet part should be a multi-stage wet press, preferably three or more stages of wet press, and a smooth press at the last stage of the press part. Growl is provided. (4) Use a tension press during the drying of the wet paper. Specifically, for example, a multi-stage tension press as described in JP-A-3-29945 is performed on wet paper.

 (5) After making the base paper, perform calendar processing using a machine calendar, a super calender, a heat calender, etc. Specifically, for example, it is preferable to perform a thermal rendering process described in Japanese Patent Application Laid-Open No. 60-126379.

 As the pulp constituting the base paper, it is advantageous to use appropriately selected natural pulp as described above, but if necessary, use synthetic pulp or synthetic fiber other than natural pulp. May be used. The natural pulp is bleached normally with chlorine, hypochlorite, and chlorine dioxide bleaching, as well as extraction or alkali treatment with oxidation and, if necessary, oxidation with hydrogen peroxide, oxygen, etc. Wood pulp of softwood pulp, hardwood pulp, and softwood pulp mixed pulp that has been subjected to bleaching and the like and a combination of these treatments is used. , ° Lup, Foodano ,. You can use a variety of things, such as rups.

Also, as described above, various water-soluble polymers or hydrophilic colloids or latex, antistatic agents, The composition consisting of additives is contained by size press, tab size press, or blade coating, or by means of a coating such as jane knife coating. Or it can be painted. As a water-soluble polymer or a hydrophilic colloid, disclosed in Japanese Patent Application Laid-Open No. Starch-based polymer, polyvinyl alcohol-based polymer, gelatin-based polymer, polyacrylamide-based polymer, cellulosic polymer, etc. Examples of the emulsions and latexes include petroleum resin emulsions described in JP-A-55-42027 and JP-A-1-1805338. Emulsions or copolymers of copolymers containing at least lenic acid and acrylic acid (or methacrylic acid) or latex or styrene-butadiene Diene-based, styrene-acrylonitrile-based, vinyl acetate-acrylic, ethylene-vinyl acetate-based, vinyl acetate-methyl methacrylate-based copolymers and the like As an antistatic agent such as emulsion or latex of these carboxyl-modified copolymers, sodium chloride is used. Alkali metal salts such as tritium and potassium chloride, alkaline earth metals such as potassium chloride and barium chloride, and colloidal metals such as colloidal silica Pigments such as organic antistatic agents such as oxides and polystyrene sulfonates, such as clay, kaolin, carbonated calcium, talc and barium sulfate And pH-adjusting agents such as titanium oxide, hydrochloric acid, phosphoric acid, citric acid, caustic soda, and other additives such as the coloring pigments, coloring dyes and fluorescent brighteners described above. It is advantageous to incorporate them in an appropriate combination.

There is no particular limitation on the thickness of the base paper, but the basis weight is preferably 20 to 200 g Zm ² .

The surface of the support for image material of the present invention on the side where the image forming layer of the base paper is provided is coated with a resin capable of forming a film. Is preferred. As such a resin capable of forming a film, a thermoplastic resin such as a polyolefin resin, a polycarbonate resin, a polyester resin, or a polyamide resin is preferable. Among them, a polyolefin resin is more preferred from the viewpoint of melt-extrusion coating properties, and a polyethylene resin is particularly preferred. Examples of such polyethylene resins include low-density polystyrene resins, medium-density polystyrene resins, high-density polyethylene resins, and linear low-density polyethylene resins. Various resins such as styrene resins, copolymers of ethylene and propylene, butylene, and other olefins, carboxy-modified polyethylene resins, and mixtures thereof Can be used. The various density of, MFR, molecular weight, but you can use those molecular weight distribution, typically, density 0. 9 1 ~0. 9 7 g / cm 3 range, MFR 1 ~ 3 0 g / 1 0 min, a molecular weight Those in the range of 20,000 to 250,000 can be advantageously used alone or as a mixture. Further, it may be coated with an electron beam-curable resin described in Japanese Patent Publication No. 60-171004.

The surface of the second resin layer of the resin-coated paper of the present invention is subjected to an activation treatment such as a corona discharge treatment or a flame treatment. It is possible to apply an undercoat layer as described in Japanese Patent Application Laid-Open No. 9-27440, Japanese Patent Application Laid-Open No. H10-12551, and Japanese Patent Application Laid-Open No. Hei 1-166035. You. Also, after performing an activation treatment such as a corona discharge treatment or a flame treatment on the surface of the first resin layer, it is possible to apply various back coat layers to prevent static electricity and the like. . Ma In addition, the nocturnal coating layer contains the publications of Japanese Patent Publication No. 52-180200, Japanese Patent Publication No. 57-99059, and Japanese Patent Publication No. 57-53940. Inorganic antistatic described in JP-B-58-56859, JP-A-59-218449, JP-A-58-184414, etc. , An organic antistatic agent, a hydrophilic binder, a latex, a curing agent, a pigment, a surfactant, and the like can be appropriately combined and contained.

 Further, as a result of diligent studies conducted by the present inventors, a method for producing a resin-coated paper by extrusion-coating one side of a base paper with a polyethylene-based resin is disclosed. When the extruder is melted and extruded, the resin pressure at the tip of the screw of the extruder is higher than the critical resin pressure (Pc). It has been found that the object of the invention is achieved particularly effectively.

The critical resin pressure described above (Pc) is determined Ri by the following method, P c =. (Z - 77 - CSR) / 9 8 X 1 0 5 · H) (2) in here, Z is scan click The length of the rewind

 Ζ = 7Γ · η · D Zcos θ

Where Pc is the critical resin pressure at the tip of the screw (Kgf / cm ² )

 7}: Viscosity of resin at 240 ° C at shear rate given by (TTND) / (60H) (N is one screw rotation)

CSR: Critical shear rate of resin (1 second) H: Depth of screw groove at bottom of hopper (cm) n: Number of screw pitch D: Barrel inner diameter (cm)

 0: Screw pitch angle (degrees)

 The resin pressure (the resin pressure before the breaker plate) at the tip end of the screw extruder used in the present invention can be easily measured with a commercially available resin manometer installed on the extruder. it can. At this time, the point where the resin pressure does not change while the extruder is filled with the resin and the screw is not rotated is defined as a point where the resin pressure is zero.

 If the resin pressure at the screw tip of the extruder does not satisfy the critical resin pressure according to the above formula (2) or more, it is not preferable because the formation of gel in the resin layer is insufficient.

 As a method of increasing the resin pressure, a resin having a low melt flow rate (hereinafter, simply referred to as MFR) specified in JISK 670 as much as possible within the scope of the present invention is used. How to use, how to reduce die opening, how to reduce opening area of breaker plate in extruder, insert screen pack into resin flow path in extruder Methods, increasing the number of screen packs, screening with a large number of meshes, using a hook, etc. Two or more can be used in combination.

Also, in practice, it is preferable that the critical resin pressure be small in order to widen the operation range during extrusion melt coating. As a method for reducing the critical resin pressure, a resin having a viscosity or a critical shear rate as low as possible within the range permitted by the present invention is used. There are various methods, such as a method for shortening the screw deployment length, and the like. These methods can be used alone or in combination of two or more.

 In addition, if the extruder is operated at a reduced rotation speed due to cleaning of the die slip, switching of resin, etc., gel may be generated, which may hinder the operation. However, according to the present invention, the generation of gel can be suppressed by setting the resin pressure to be equal to or higher than the critical resin pressure.

 In order to extrude and coat the polyethylene resin melt-extruded from the die of the extruder on the base paper, the base paper may be directly extrusion-coated, or the base paper and the polyethylene resin may be extruded. In order to enhance the adhesive strength with the resin, the adhesive surface of the base paper is subjected to a known surface activation treatment such as corona discharge treatment, flame treatment, anchor coat treatment, etc. It may be extrusion coated.

 The extrusion coating can be carried out by using a known method and apparatus. For example, a polyethylene resin is extruded from a die of an extruder at a resin temperature of 280 to 34 ° C. The molten thin film is guided to a pressure roll, and the base paper and the pressure roll, on which the adhesive surface is untreated or which has been subjected to the above-described surface activation treatment and similarly guided to the pressure roll, are formed. And extrusion coating through a cooling roll.

 The thickness of the polyethylene resin layer is not particularly limited, but is usually in the range of about 5 to 50.

Examples of the polyethylene resin used as the resin layer include: high-density polyethylene, low-density polyethylene, or medium-density polyethylene. Polyethylene is used.

 The prevention of gel formation according to the present invention is considered to be due to the viscoelastic properties of the resin at a high resin temperature during melt extrusion coating, and the resin pressure at the screw tip is critical resin. It is considered that the increase in the pressure was caused by a decrease in the gelation opportunity, gel grinding, and improved kneading.

 Furthermore, the present inventors have conducted intensive studies and found that the center plane in the machine direction at a cutoff value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter of the first resin. It has been found that when the average roughness SRa is in the range of 0.6 to 2.0 m, the object of the present invention is particularly effectively achieved.

The center plane average roughness SRa at a cut-off value of 0.8 mm measured using a stylus type three-dimensional surface roughness meter referred to in this specification is defined by the following equation.

In the above formula, W x represents the length of the sample area in the X-axis direction (papermaking direction), and Wy represents the length of the sample area in the Y-axis direction (direction perpendicular to the papermaking direction). And Sa represents the area of the sample surface area.

Specifically, the SE-3AK model and SPA-11 model manufactured by Kosaka Laboratories Ltd. were used as the stylus type 3D surface roughness meter and 3D roughness analyzer. 0.8 mm, W x = 20 mm. W y = 8 mm. Therefore, it can be obtained under the condition of S a = l 60 mm ² . In addition, sampling is performed at 500 points as data processing in the X-axis direction, and 17 lines or more are performed as scanning in the X-axis direction.

 An object of the present invention is to provide a resin-coated paper in which the first resin layer has a center plane average roughness SRa in a range of 0.6 to 2.0 m, and has a specific resin as a resin for the first resin layer. It has been found that a synergistic effect can be attained by using a resin composition containing a liethylene-based compound resin as a main component. In particular, according to the present invention, the contamination of the cooling roll during the production of the resin-coated paper-type image material support is synergistically improved, and in the image material support or the image material having the support according to the present invention, the cooling There is no quality problem due to the transfer of the stains. Also, the object of the present invention is remarkably achieved by processing the center surface average roughness SRa of the backside resin layer surface in the range of 0.8 to 1.6 μm as referred to in this specification. Was found. Further, an object of the present invention is to provide a low-density polyethylene resin or a medium-density polyethylene resin in a polyethylene-based compound resin, It was found that the rate was significantly achieved by using a rate of 0.2 g Zl 0 min or more and lg Z 10 min or less.

As described above, the first resin layer of the resin-coated paper is preferably processed to have a center plane average roughness SRa in the range of 0.6 to 2.0 m. If the center plane average roughness SRa is less than 0.6 jm, it is difficult to sufficiently prevent the generation of dirt on the cooling roll. In addition, when the support for the image material or the image material having the support is wound into a roll after production, the front and back surfaces tend to adhere and be blocked. On the other hand, even when the center plane average roughness SRa is greater than 2.0 m, the prevention of the generation of dirt on the cooling roll is reduced, and the support for the image material or the image material having the support is rolled. There is a problem that the surface tends to become cloudy when wound up. The center surface average roughness SRa of the backing resin layer surface of the image material support in the present invention is preferably in the range of 0.8 to 1.6 μm.

 As a method of processing the center surface average roughness SRa of the first resin layer surface to a range of 0.6 to 2.0 m, a cooling roll having a roughness such that SRa in the range is obtained is used. It may be used. Specific examples of the manufacturing method of the chill roll include the embossing method described in Japanese Patent Application Laid-Open No. 60-69444 and Japanese Patent Application Laid-Open No. 62-15047. It can be manufactured by the etching method, dry blast method, liquid honing method, etc. The liquid honing method is preferred. It is preferable that the resin-coated paper is manufactured using a cooling roll before use, and the center-surface average roughness SRa of the back surface of the resin-coated paper is measured and confirmed.

As described above, a composition comprising various water-soluble polymers or hydrophilic colloids or latexes, antistatic agents, and additives is coated on a base paper using a size press or tab size. Coating such as press or blade coating, air-naive coating It can be included or applied depending on the application. As a water-soluble polymer or a hydrophilic colloid, a starch-based polymer and a polyvinyl alcohol-based polymer described in Japanese Patent Application Laid-Open No. 1-265337 can be used. Emulsion, latex, gelatin-based polymer, polyacrylamide-based polymer, cellulosic polymer, etc. Emulsion, ethylene and acrylic acid (or methacrylic acid) described in JP-A-55-42027 and JP-A-1-180538. ) Or at least a copolymer, emulsion, latex, styrene-butadiene, styrene-acrylic, acetic acid Vinyl-acrylic, ethylene mono-vinyl acetate, butadiene-methyl methacrylate copolymers and their carboxy Alkali metal salts such as sodium chloride, potassium chloride, etc. as antistatic agents such as emulsion copolymer or latex of modified copolymer, calcium chloride, etc. Alkaline earth metal salts such as barium chloride Colloidal metal oxides such as colloidal silica, organic antistatic agents such as polystyrene sulfonate, etc. Pigments such as cream, kaolin, calcium carbonate, talc, barium sulfate, titanium oxide, etc., and phosphate adjusters such as phosphoric acid and quencher It is advantageous to incorporate an appropriate combination of additives such as acid, caustic soda, and the above-mentioned coloring pigments, coloring dyes, and optical brighteners.

As the base paper that is preferably used, a flat paper having a Bekk smoothness of 100 seconds or more specified by JISP 8119 is used. Those having a smooth surface are preferred, and those having a smooth surface of 200 seconds or more are more preferred. As a method for producing a base paper having a Beck smoothness of 100 seconds or more, generally, a large amount of hardwood pulp that is short and easy to smooth is used, and a long fiber is obtained by a beater. Beat it to a minimum. Specifically, the beating of the pulp is carried out so that the weave length of the pulp after the beating becomes 42-mesh residue of 20-45% and freeness of 200-350 CSF. This is preferred. Next, regarding the stock slurry to which the internal additives have been added, see JP-A-58-37642, JP-A-61-260240, JP-A-61 (1) Adopting an appropriate papermaking method as described in Japanese Patent Publication No. 2 8 4 7 6 2 etc. and using a paper machine usually used such as a fourdrinier paper machine or a round mesh paper machine to form a uniform formation The paper is processed so as to obtain a smoothness, and after the paper formation, a calendering treatment is performed using a machine calendar, a super calender, a heat calender, etc., and a Bekk smoothness of 100 seconds. The above base paper can be manufactured. The thickness of the base paper used in the practice of the present invention is not particularly limited, but preferably has a basis weight of 20 to 250 g / m ² .

 EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples as long as it does not exceed the gist.

Example 1

HDPE with MFR of 15.0 g / 10 min, density O.SST g Zcm ³ , and a critical shear rate of 60 (1 Z seconds) (see Table 1 below) A) 70 parts by weight, MFR 0.6 g / l 0 min, density 0.992 4 g / cm ⁸ , molecular weight 500,000, proportion of 15% by weight or more, and critical shear rate of 0.0 6 (1 ns) LDPE (e in Table 1) 30 parts by weight was melt-mixed beforehand, and the mixture was extruded at a resin temperature of 320 at a basis weight of 170 g Zm ^{2 by} an extruder. It was manufactured by extrusion coating on high paper to a thickness of 25 / m.

 As a method for evaluating the moldability during melt extrusion coating of the resin, the length of the resin-coated portion in the horizontal direction is measured to evaluate the degree of neck-in, and the line of the molten resin film is evaluated. Comprehensive evaluations were made of the degree of occurrence, the presence or absence of film breakage depending on the degree of drawdown, and the forming processability such as flow instability due to surge or draw resonance.

 The evaluation criteria are as follows: 〇: good, △: slightly bad but no practical problem, X: poor and some practical problem.

 As a method for evaluating the adhesiveness between the base paper and the resin layer of the resin-coated paper, the sample is separated into the base paper layer and the resin layer, and the area ratio of the base paper layer adhered to the separated resin layer is measured. Thus, the adhesiveness between the base paper and the resin layer was evaluated. The evaluation criteria are as follows: ：: Area ratio of 100% is good, and △: Area ratio is less than 100% and is 80% or more. Adhesion is slightly poor, but there is no practical problem. Degree, X: The area ratio is less than 80%, the adhesiveness is poor, and there are some practical problems.

The method for evaluating the gel during melt extrusion of the resin was as follows: a set temperature of 32 ° C, 8 hours under conditions of 2.5 kg per hour Off I Lum shaped extrusion was 0.0 1 full I Honoré厶中number of 0. 1 mm or more gel that put into the m ² after measured, you compared to the initial value this and the by Ri gel Was evaluated. The evaluation criteria are as follows: ：: The number of gels after 8 hours does not change from the initial value, and X: The degree to which the number of gels after 8 hours has increased from the initial value. Secondary of resin-coated paper The processability was evaluated by cutting the sample with a commercially available guillotine and evaluating the cutability based on the degree of fluffing of the cut, and rubbing the resin layers of the resin-coated paper with each other. When combined, the friction resistance depending on the degree of scratches on the resin layer surface and the secondary workability such as the stiffness of the resin-coated paper were comprehensively evaluated. Evaluation criteria are: 〇: good,

△: Slightly bad but not practically problematic, X: Poorly badly practically problematic.

 Table 1 shows the physical properties of HDPE and LDPE used in this example, and Table 2 shows the evaluation results of the obtained resin-coated paper obtained by the above evaluation method.

Examples 2 to 9

 Instead of the combination of HDPE and LDPE used in Example 1, various resin compositions combining HDPE and LDPE shown in Table 1 were used, respectively, and resin-coated paper was obtained in the same manner as in Example 1. Table 2 shows the evaluation results of these methods using the above evaluation methods.Examples 10 to 18

Examples 10 to 17 were the same as Example 1 except that the combinations of HDPE and LDPE used in Example 1 were replaced with various resin compositions combining HDPE and LDPE shown in Table 1, respectively. Similarly, a resin-coated paper was obtained. Table 3 shows the results of these evaluations using the above evaluation method.

 In Example 18, HDPE and LDPE resin compositions of the same type and composition as in Example 1 were used, and were not melt-mixed but dried and mixed as they were. A resin-coated paper was obtained in the same manner as in Example 1. Table 3 shows the evaluation results by the above evaluation method.

Further, the resin-coated paper obtained in Examples 1 to 9 was immersed in a commercially available aqueous solution of hypochlorous acid for 3 days, and the resin layer separated from the base paper was washed with water, air-dried, and then subjected to MFR, When the density and the critical shear rate were measured by the methods described above, the MFR force was 1.0 to 40 g / 10 minutes and the density was 0.930 to 0.971 g for all resin layers. / cm ³ , and the critical shear rate was less than 20 (1 second).

table 1

MFR density good 1.5 million

 Π / 5 / UTT 5 / HI • lin

 Rare% 1 / sec

A 15 0.967 ― 60 High density polyethylene B 20 0.967 70

(HDPE) C 7 0.967 1 27

 U Δ) U.9bU 70

E 30 0.960 80 h e 0.6 0.924 15.0 0.06 Low density polyethylene f 0.9 0.924 13.9 0.20

(LDPE) g 1.2 0.918 15.6 0.53 h 3.5 0.926 9.1 1.6 i 0.8 0.923 4.1 1.5 j 0.4 0.923 9.2 0.32

Table 2

Table 3

HDPE LDPE

 Workability Note Raw Gel Workability Example Illustrated LL.

 Infarction PC it 1 / sec

10 A 95 e 5 30.0 X X X 〇

11 C 95 e 5 15.0 X X X 〇

12 A 50 e 50 1.0 〇 〇 〇 X

13 D 80 g 20 17.0 〇 〇 X 〇

14 A 80 h 20 17.0 X 〇 X 〇

15 D 80 h 20 20.0 X 〇 X 〇

16 A 80 i 20 20.0 X 〇 X 〇

17 A 80 j 20 9.0 X 〇 〇 〇

18 A 70 e 30 X Δ XX

From the results in Table 2, it can be seen that the resin composition containing 90 to 65 parts by weight of HDPE and 10 to 35 parts by weight of LDPE having the physical properties defined in the present invention, and whose critical shear rate is Resin-coated paper having a resin layer of 10 (1 Z seconds) or less (Examples 1 to 9) has good moldability and adhesiveness, and has low gel and excellent quality. Is understood.

 On the other hand, from the results shown in Table 3, when the requirements of the present invention are not satisfied, for example, when the HDPE content is more than 90 parts by weight (Examples 10 to 11), the moldability, Poor nature and many gels. When the content of HDPE is less than 65 parts by weight (Example 12), the formability is poor, and when the critical shear rate of LDPE is greater than 0.5 (1 / sec) (Example) In 13 to 16), there are many gels, and when the ratio of the molecular weight of 500,000 or more in LDPE is less than 10% by weight (Examples 14 to 17), the moldability is poor.

 Furthermore, when the critical shear rate of the resin composition of HDPE and LDPE is higher than 10.0 (1 nosec) (eg, 10, 11, and 13 to 16), the gel content is high. Further, when the composition of HDPE and LDPE is dry-mixed without being melt-mixed (Example 18), the molding processability is poor and a favorable result cannot be obtained.

 ADVANTAGE OF THE INVENTION According to this invention, the molding processability of a resin layer is favorable, the adhesiveness of a resin layer and a base paper is excellent, and the polyethylen resin coating paper with few gels is provided.

Example 1 9 A mixture of hardwood bleached sulfite pulp and hardwood bleached craft pulp 1: 1. The pulp is beaten to Canadiaan's Standard Freeness of 320 m1, and 3 parts by weight of carotinated starch and anionized are added to 100 parts by weight of pulp. 0.2 parts by weight of polyacrylamide, alkyl ketene dimer emulsion (as ketene dimer) 0.4 parts by weight, polyaminopolyamide the filtrate le arsenide drill down resin 0.4 parts by weight of added pressure, to produce a paper weighing 1 6 0 m ^2. The obtained wet paper is dried at 110 ° C, and then 3 parts by weight of a carboxyl-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent whitening agent, and 0.002 parts by weight of a blue dye parts, Na Application Benefits U arm 4 parts by weight chloride, the click E phosphate 0.2 parts by weight of water 9 3 parts by weight or et consisting impregnating solution ² 5 g / m 2 was impregnated, with hot air at 1 1 0 ° C It was dried and further subjected to super-force rendering at a linear pressure of 90 kg / cm to produce a photographic support base paper. At this time, the Bekk smoothness of the base paper was 200 seconds.

 Next, the base paper surface (back surface) opposite to the side on which the image forming layer is coated is subjected to a corona discharge treatment, and then the polyethylene resin composition shown in Table 4 is applied to the back surface at a resin temperature of 3. The first resin layer was formed by extruding and coating at 20 ° C. the resin coating amount shown in Table 4 at a running speed of the base paper of 150 m / min.

Subsequently, after the surface of the base paper was subjected to a corona discharge treatment, a low-density polyethylene resin (density 0.920 g / cm ² , MFR = 8.5 g / 10 min) 4 7.5 wt%, and the A1 ₂ 0 ₃ minutes against the hydrated Aluminum Niu arm (vs. dioxide Ji data down Masterbatch of titanium dioxide pigment consisting of 50% by weight of anatase type titanium dioxide pigment and 2.5% by weight of zinc stearate, surface-treated with 0.75% 20 parts by weight, low Density Polyethylene resin (density 0.920 g / cm ³ , MFR = 4.5 gZlO) 65 parts by weight and high density Polyethylene resin (density 0.970 gZcm ³ , MFR = 7.0 min) 1

The resin composition consisting of 5 parts by weight was melt-extruded at a resin temperature of 320 ° C and the resin coating amount shown in Table 4 at a running speed of the base paper of 150 m / min and coated. Then, a second resin layer was formed. The front and back sides of the polyethylene resin were melt-extruded and extruded by a so-called tandem method in which the extrusion coating was performed sequentially. At that time, the surface of the second resin layer containing the titanium dioxide pigment of the resin-coated paper was processed into a glossy surface, and the surface quality of the first resin layer was processed into a matte surface such as paper. After the corona discharge treatment on the first resin layer surface of the paper, the following back coat coating solution was applied on-machine. As a dry Weight content, co Roy de shape Shi Li Ca: styrene Les emission system latte click scan = 1: 1 to become further of port Li steel les Nsurufu O phosphate soda 0. 0 ² 1 gZm 2 other suitable amount of back-co including coating aids, etc. - DOO coating liquid la te click scan component (in solid weight calculation) and to 0. 2 1 gZm image material and coating of the coating amount becomes ² A support was obtained.

As described above, the moldability of the polyethylene resin compositions for the first and second resin layers, the degree of the generation of gel-like foreign matter, and the degree of formation are obtained when the support for the image material is produced. Sample The evaluation method of the performance as a support for an image material was evaluated by the following method.

 As a method for evaluating the moldability of the polyethylene resin composition for the first resin layer at the time of manufacturing the support for the image material, the lateral length of the resin-coated portion on the back surface is measured. In addition to assessing the degree of neck-in, the degree of streaking of the molten resin film, the presence or absence of film breakage due to the degree of drawdown, surging or draw resonance Comprehensive evaluations were made of moldability such as flow instability. The evaluation criteria are as follows: 〇: good, △: somewhat bad, but practically no problem, X: bad, some practical problem.

As a method for evaluating the gel-like foreign matter at the time of melting and extruding the polyethylene resin composition for the first resin layer, a set temperature of 320 and an hour per hour are used. the initial values and measured 0. 0 1 m ² of the full number of 0. 1 mm or more gel-like foreign matter in Lee in Lum after pushed out to 8 hours full i le厶状under conditions of a kg By comparison, the gel-like foreign matter was evaluated. The evaluation criteria were as follows: ：: The number of gel-like foreign substances after 8 hours did not change from the initial value, Δ: The number of gel-like foreign substances after 8 hours increased slightly, but there was a practical problem. To some extent, X: After 8 hours, the number of gel-like contaminants increased significantly from the initial value, indicating that there was some practical problem.

As a method for evaluating the adhesiveness between the base paper of the imaging material support and the first resin layer, each sample was stored in a constant temperature and humidity chamber at 50 ° C and 60% RH for 1 day. Sample base paper layer and first resin layer The adhesiveness between the base paper and the first resin layer was evaluated by measuring the area ratio of the base paper layer adhered to the separated resin layer. Evaluation criteria are as follows: 〇: good at 100% area ratio; △: 80% or more when area ratio is less than 100%; X, area ratio is less than 80%, adhesiveness is poor and there is some practical problem.

The curl properties of the image material support were evaluated in the following manner. First, after a corona discharge treatment, a blue-sensitive emulsion layer containing a yellow color coupler, an intermediate layer containing a color-mixing inhibitor, and a magenta layer on the surface of a second resin layer containing a titanium dioxide pigment of an image material support. ultraviolet absorbing layer containing a green-sensitive emulsion layer ultraviolet absorber containing a color coupler, color photographic paper total Zerah Chi down provided red-sensitive emulsion layer and a protective layer containing a cyan color-forming coupler is 8 g Z m ² It was created. 0 colors sensitive emulsion layer in the silver nitrate. 6 g Z m contains the corresponding silver chlorobromide to ^2, further formation of the silver halide, other gelatin required dispersion and film formation, an appropriate amount of capsules re inhibitor, It contained sensitizing dyes, coating aids, hardeners, thickeners, and appropriate amounts of filter dyes. Next, the prepared color printing paper was stored at 35 ° C. At room temperature for 5 days. After color development, the color paper was 8.2 cm x 11.7 cm at 20 ° C and 40% RH. The state of the curl of the color print of the size was evaluated. The evaluation criteria were as follows: ；; slightly minor (curl to the back coat layer side) and extremely flat, good roll physical properties, △: curl, but practically problematic What X: The curl is large, indicating that there is some practical problem.

 As a method for evaluating the cutting property of the support for image materials, the above color photographic paper was subjected to a longitudinal print force of 11.7 cm with a longitudinal print cutter. It was cut into pieces as required, and the condition of the cut surface was evaluated. Evaluation criteria are as follows: ：: Almost no whisker generated, good cutting performance, △: Slight whisker generation, but X: whisker generation to the extent that there is no practical problem Most of them have poor cutting properties and have some practical problems. As a method for evaluating the smoothness of the support for an image material, the surface of the above color photographic printing paper was observed with oblique light, and the apparent glossiness was visually evaluated. The evaluation criteria are as follows: 見: high apparent glossiness, good smoothness of the support; △: slightly low glossiness, slightly inferior To the extent that there is no practical problem, X: the appearance is low, the support has poor smoothness, and there is some practical problem.

The results obtained are shown in Table 4.

Table 4

(X): Difficulty of gelling from holding

Note that (Note 1) to (Note 3) in Table 1 are as follows:

(Note 1) HDPE: High-density polyethylene resin with a density of 0.967 g / cm ³ and an MFR of 15 gZ 10 minutes.

(Note 2) LDPE: Density 0.924 gZcm ³ , MFR = 0.6 g / 10 min, fraction with molecular weight of 500,000 or more = 15 wt% Critical shear rate = 0.06 (1 / S) low-density polyethylene resin.

 (Note 3) Polyethylene resin composition preparation method ~ Compound: A pellet resin composition prepared by melting and mixing HDPE and LDPE in advance using a kneading extruder. It was used as a kit. Simple mixing: HDPE and LDPE were added to a melt extruder while being used as a simple mixture.

From the results shown in Table 4, the difference between the resin coating amounts in the first and second resin layers is 3 gZm ² or more, and the polyethylene resin in the back resin layer is the high-density resin according to the present invention. A resin prepared by previously melting and mixing 90 to 65 parts by weight of polyethylene resin and 10 to 35 parts by weight of low-density polyethylene resin. Some imaging material supports (samples Να2, Να3, Να4, Να5, Na6, and Ni11) have good molding processability of the polyethylene resin composition, and It is clearly understood that this is an excellent support for image materials, which does not generate gel-like foreign matter and has good adhesiveness between base paper and resin layer, curl physical properties, cutting properties and smoothness. . In particular, from the overall performance of the support for image materials, the amount of resin coating in the first and second resin layers is It is clear that the difference is preferably larger than 3 gZm ² , and the content of HDPE is preferably in the range of 85 to 70 parts by weight.

On the other hand, when the content of the high-density polyethylene resin is more than 90 parts by weight (sample Να1), the moldability of the polyethylene resin composition is poor and the gel-like There is a lot of foreign matter, and the adhesion and cutting property between the base paper and the resin are poor, which is a problem. If the content of the high-density polyethylene resin is less than 65 parts by weight (sample Να ΐ 2) is a problem because of poor curl properties. When the polyethylene resin composition is simply mixed (sample Nc 10), the moldability and cutability of the polyethylene resin composition are poor. In addition, gel-like foreign matter is often generated from the beginning, which is a problem. Further, when the difference between the resin coating amounts in the first and second resin layers is smaller than 3 gZm ² (samples Να7, No. 8 and Να9), the cutting property and the smoothness are poor, which is a problem. is there.

Example 2 0

Instead of the polyethylene resin composition for coating the back surface used in the sample # α5 of Example 19, the polyethylene resin shown in Table 5 was used instead of the polyethylene resin shown in Table 5 in the formulation shown in Table 6. Example 19 was carried out in the same manner as in Sample No. 5 except that it was used as a compound resin composition prepared in the same manner as in Sample No. 5 of Example 19. Table 5

MFR density good 1.5 million

Resin type (g / 10 min) (g / cm ³ )

 (Chapter (1 / second)

A 15 0.967 60

B 20 0.967 70 High density polyethylene C 7 0.967 _ 27 Purpose (HDPE) D 20 0.960 _ 70

 E 28 0.967 80J¾ ±

F 38 0.967 ― 80i¾ ±

G 45 0.967 80J¾ ± h 0.6 0.924 15.0 0.06 i 0.9 0.924 13.9 0.20 Low density polyethylene j 1.2 0.924 13.4 0.36 Purpose (LDPE) k 1.2 0.918 15.6 0.53

1 3.5 0.926 9.1 1.6 m 0.8 0.923 4.1 1.5 n 0.4 0.923 9.2 0.32

Table 6 shows the obtained results.

Table 6

 Combination of polyethylene column for layer 1 layer and fiber for layer 1 for layer 1

Xie Polyethylene Tree Polyethylene Tree Gel 1st Tree

No. HD P E L D P E Difficult oil layer and curl of fat Grease slip property Outgoing Species ratio Species ratio (, above 1 // sec)? ? Sex

 mm)

 13 A 75 h 25 3.1 〇 〇 〇 〇 〇 〇 〇

14 A 80 h 20 4.4 〇 〇 〇 〇 〇 〇

15 B 65 h 35 1.7 〇 〇 〇 Δ 〇 〇

16 B 70 h 30 2.8 〇 〇 〇 〇 〇 〇

17 B 75 h 25 3.7 〇 〇 〇 〇 〇 〇

18 B 80 h 20 6.3 〇 〇 〇 〇 〇 〇

19 D 80 h 20 6.7 〇 〇 〇 Δ 〇 〇

20 A 80 i 20 7.0 〇 〇 〇 〇 〇 〇

21 A 80 j 20 8.0 〇 Δ 〇 〇 〇 〇

22 E 80 h 20 7.3 〇 〇 〇 〇 〇 〇

23 F 80 h 20 8.2 Δ Δ Δ 〇 〇 〇

24 D 80 k 20 17 〇 X 〇 Δ 〇 〇

25 A 80 1 20 17 X X 〇 〇 〇 〇

26 D 80 1 20 20 X X Δ Δ 〇 〇

27 A 80 m 20 20 X X 〇 〇 〇 〇

28 A 80 n 20 9.0 X △ 〇 〇 〇 〇

29 C 80 h 20 7.5 〇 〇 〇 〇 X 〇

30 G 80 h 20 10.4 XXX 〇 〇 〇

The results in Table 6, the first port Re ethylene les down resin in the resin layer is an MFR of 1 0 gZ l 0 minutes ~ 4 0 gZ l 0 min, dense potentiation density of 0. 9 6 0 gZcm ³ or more re ethylene les down resin 9 0 by weight parts to 6 5 parts by weight and MFR of 0. 2 gZ l O min ~ 2/1 0 min, a density of 0. 9 3 5 g Roh cm ³ or less, molecular weight 5 0 10,000 or more Of low-density polyethylene resin having a fraction of 10% by weight or more and a critical shear rate of 0.5 (1 / sec) or less is melted and mixed in advance with 10 parts by weight to 35 parts by weight. The support for an image material according to the present invention (sample # α13 to Δα2), which is a prepared resin composition having a critical shear rate of 10 (1 second) or less. 3) has good molding processability of the polyethylene resin composition, does not generate gel-like foreign matter, and further has an adhesive property between the base paper and the resin layer, a curl property, a cut property and a smoothness. Excellent with good properties It can be clearly seen that this is a supported image material support.

In particular, as the low-density polyethylene resin, those having an MFR of less than 1 gZ10 minutes are preferable from the viewpoint of preventing the generation of gel-like foreign substances (samples Ναΐ4 and Να2 It can be clearly seen that 0 and sample Ν (comparison with 21) .The high-density polyethylene resin used in the present invention has a density of 0 from the viewpoint of curl physical properties. It is preferable to use a sample with a particle size of 96.2 e / cm or more (comparison of sample Να14 and Να18 with sample Να19). Also, the moldability, the effect of preventing gel-like foreign matter, the base paper and resin From the viewpoint of the adhesion to the layer, those having an MFR in the range of 10 gZ10 min to 30 gZ10 min are preferable. (Comparison of sample NOL I 4, Να 18, and ffo 22 with ΝΟ · 23) Further, as the compound resin composition used in the practice of the present invention, those having a critical shear rate lower than 8 (1 second) are preferable (sample Nos. 13 to Να20). And 22 with Sample Nos. 21 and 23).

 On the other hand, when the MFR of the low-density polyethylene resin is larger than 2% / 10 minutes (sample Να26), the molding processability and the degree of generation of gel-like foreign matter are poor, which is problematic. On the other hand, if the low-density polyethylene resin has a molecular weight of 500,000 or more and a fraction of less than 10% by weight (sample Not26 ~! Fo28), the molding processability is poor. This is a problem and tends to increase the generation of gel-like foreign matter. If the MFR force of the high-density polyethylene resin is greater than 0% / 10 min (Sample No. 30), the moldability, the degree of gel-like foreign matter generation, the base paper and the resin This is a problem because of poor adhesion to the layer. In addition, when the critical shear rate of the compound resin composition is larger than 10 (1 second) (samples Να24 to Not27 and Να30), the generation of gel-like foreign matter is high. It is a problem.

According to the present invention, no gel-like foreign matter is generated in the resin layer on the side opposite to the side on which the image forming layer is provided, and the adhesiveness between the resin layer and the base paper is good. As a result, it is possible to provide an excellent resin-coated paper-type image material support which has good curl properties, cutability and smoothness, can be produced at high speed, and can be produced stably. Example 2 1

^{MFR 1 5. 0 8 / / 1} 0 1 ^ 11, density 0.9 6 7 dense potentiation Re ethylene les down 7 0 parts by weight of GZcm ³ and MFR O. 6 g / 1 0 min , density 0.9 2 Pre-melt 30 parts by weight of low-density polyethylene with 4 g / cm ³ , a molecular weight of 500,000 or more, a fraction of 15% by weight, and a critical shear rate of 0.06 (1 second) The mixture was mixed and extruded on a highly smooth paper having a basis weight of 170 gZm ^{2 by} an extruder at a resin temperature of 320 ° C. so as to have a thickness of 25 m.

 As a method for evaluating the moldability during melt extrusion coating of the resin, the length of the resin-coated portion in the horizontal direction is measured to evaluate the degree of neck-in, and the line of the molten resin film is evaluated. Formability was evaluated comprehensively, including the degree of occurrence, the presence or absence of film breakage due to the degree of drawdown, and the instability of flow due to serration or draw resonance. The evaluation criteria are as follows: ：: good, △: slightly bad, but no practical problem, X: poor, practical to some extent.

As a method for evaluating the adhesiveness between the base paper and the resin layer of the polyethylene resin-coated paper, the sample is separated into the base paper layer and the polyethylene layer, and the separated polyethylene layer is separated. The adhesiveness between the base paper and the resin layer was evaluated by measuring the area ratio of the base paper layer adhered to the base layer. The evaluation criteria are as follows: ：: Area ratio of 100% is good, and △: Area ratio is less than 100%, and is 80% or more. , X: The area ratio is less than 80%, the adhesiveness is poor, and there is a practical problem. Degree, represents.

As a method for evaluating the gel at the time of melt extrusion of the resin, a set temperature of 32 ° (2.5 kg per hour, after extruding the film into a film for 8 hours) 0. 0 1 m 0 that put the full I le厶中of ^2.1 Ri by the and this for measuring the number of mm or more gel compared to the initial value was evaluated gel. is an evaluation criteria , 〇: The number of gels after 8 hours does not change from the initial value X: The degree to which the number of gels after 8 hours has increased from the initial value.

 As a method of evaluating the secondary workability of a polyethylene resin-coated paper, the cutability was evaluated by the degree of fluffing of the cut edge obtained by cutting the sample with a commercially available guillotine cutter. In addition, when the resin layer surfaces of the resin-coated paper were overlapped and rubbed with each other, abrasion resistance depending on the degree of scratches on the resin layer surface and secondary workability such as stiffness of the resin-coated paper were comprehensively evaluated. The evaluation criteria are as follows: 良好: good, △: somewhat poor but not practically problematic, X: poorly and practically problematic to some extent.

Example 2 2 to 3 1

The procedure was performed in the same manner as in Example 21 except that the polyethylene resin composition was changed to the resin types shown in Table 7.

Table 7

Mr K. JS J M J

Resin type g / 10 min g / cra ³ J¾ ± fraction

 Chapter halo% 1 / sec

A 15 0.967 60 Low density polyethylene B 20 0.967 70

(HDPE) C 20 0.960 70

D 7 0.967 27 Low density polyethylene e 0.6 0.924 15.0 0.06

(LDPE) f 1.2 0.918 15.6 0.53 g 3.5 0.926 9.1 1.6

Tables 8 and 9 show the obtained results.

Table 8

HDPE LDPE m Screw Screw Weaving fiber Sample m Ratio Ratio

Military halo Aroha 1 / s rpm rpm Example 22 A 70 e 30 2.3 30 8 Example 23 A 70 e 30 2.3 60 8 Example 24 A 80 e 20 4.4 60 16 Example 25 B 70 e 30 2.8 30 10 Example 26 B 70 e 30 2.8 60 10 Example 27 C 80 f 20 17.0 85 62 Example 28 D 65 g 35 5.2 30 19 Example 29 C 80 f 20 17.0 30 62 Example 30 C 80 f 20 17.0 60 62 Example 31 A 97 e 3 40.0 60 145

Table 9

From the results in Table 8, it can be seen that gel-coated polyester resin-coated paper (Examples 22 to 27) coated under melt extrusion conditions with a screw rotation speed higher than the critical rotation speed did not generate gel. In addition, it can be clearly seen that this is an excellent polyethylene resin-coated paper having good moldability and good adhesion between the resin layer and the base paper.

On the other hand, when the MFR of high-density polyethylene is smaller than 10 g / 10 min (Example 28), the secondary workability is poor, which is a problem. If the screw speed of the extruder is lower than the critical speed (Examples 29-31), the gel is bad and a problem. In addition, the content of high-density polyethylene is 90 parts by weight. If the amount is too large (Example 31), the adhesion between the gel and the base paper and the resin layer and the moldability are poor, which is a problem.

 ADVANTAGE OF THE INVENTION According to the present invention, the resin layer has good molding processability, good adhesion between the resin layer and the base paper, and further, excellent polyethylene which can prevent gelling of the resin layer. Resin-coated paper can be supplied.

Example 3 2

A mixed pulp consisting of 50% by weight of hardwood bleached kraft pulp, 35% by weight of hardwood bleached sulfurite pulp and 15% by weight of softwood bleached sulfurite pulp has the fiber length shown in Table 10. After the beating, 100 parts by weight of the pulp, 3 parts by weight of cationized starch, 0.2 parts by weight of anionized polyacrylamide, and alkyl ketene dimer mono-emulsion (Ketene die 0.4 parts by weight of poly (amide chlorohydrin) resin and 0.4 parts by weight of an appropriate amount of fluorescent whitening agent, blue dye and red dye are added to the paper. A preparation slurry was prepared. After that, the stock slurry is placed on a fourdrinier machine running at 200 mZ to give a suitable turbulence to form a web of paper. After performing a three-stage wet press in which the linear pressure is adjusted in the range of 0 kg Z cm, treat with a smoothing roll, and then continue to dry with a dry part of 30 to 70 kg / cm. After a two-stage strain press in which the linear pressure was adjusted within a certain range, it was dried. Then, during the drying process, 4 parts by weight of lipoxy-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent whitening agent, 0.002 parts by weight of a blue dye, and sodium chloride A size press solution consisting of 4 parts by weight of lithium and 92 parts by weight of water was subjected to a size press of 25 gZm ^{2 and} dried so that the finally obtained base paper had a moisture content of 8% by weight on a dry basis. Machine calendering under the conditions described in 10 and then heat soft calendering at a temperature of 150 ° C and a linear pressure of 150 kg / cm, and a basis weight of 170 g / It was produced base paper of the image material support having a thickness unevenness exponential R py listed in Table 1 0 m ^2.

 Next, the base paper surface (back surface) opposite to the side on which the image forming layer is coated is subjected to a corona discharge treatment, and the following polyethylene resin composition is combined on the back surface in a combination described in Table 10 below. The material was melt-extruded and coated at a resin temperature of 320 ° C to a resin thickness of 26 zm at a running speed of the base paper of 150 minutes.

 The following resin compositions of the present invention (1BL) and comparative resin compositions (2BL to 4BL) were used as the polyethylene resin compositions for coating the backside of the base paper.

 Resin composition (1BL): 80 parts by weight of high-density polyethylene resin (1HD) and 20 parts by weight of low-density polyethylene resin (11d) described in Table 11 Of a polyethylene resin composed of a compound resin with a critical shear rate of 4.4 (1 Z seconds), which was previously melted and mixed using a kneading extruder. Used as pellets.

Resin composition (2BL): 80 parts by weight of high-density polyethylene resin (1HD) and 20 parts by weight of low-density polyethylene resin (11d) described in Table 11 Each pellet was added to a melt extruder with simple mixing. Resin composition (3BL): 80 parts by weight of high-density polyethylene resin (4HD) and 20 parts by weight of low-density polyethylene resin (41d) described in Table 11 Of a polyethylene resin composition consisting of a compound resin with a critical shear rate of 17 (1 Z seconds), prepared by pre-melting and mixing using a kneading extruder. Used as a tut.

 Resin composition (4BL): 50 parts by weight of high-density polyethylene resin (1HD) and 50 parts by weight of low-density polyethylene resin (11d) shown in Table 11 Of a polyethylene resin composition consisting of a compound resin with a critical shear rate of 1.0 (1 Z second) prepared by pre-melting * mixing with a melt extruder. Used as a let.

 Subsequently, the front surface of the base paper was subjected to corona discharge treatment, and then a low-density polyethylene resin (density 0.920

^{gZcm 3, MFR = 8. 5/} 1 0 min) 4 7.5 wt%, at containing hydroxide Aluminum bromide (vs. 0.7 5 wt% against to A1 ₂ 0 ₃ minutes converted into titanium dioxide emissions) 20 parts by weight of a titanium dioxide pigment masterbatch composed of 50% by weight of anatase-type titanium dinitrate pigment and 2.5% by weight of zinc stearate, a low-density polyethylene resin ( Density 0.920 gZcm ³ , MFR = 4.5 gZlO content) 65 parts by weight and high-density polyethylene resin (density 0.970 g / cm ³ , MFR = 7.0 g) The resin composition consisting of 15 parts by weight was melt-extruded and coated at a resin temperature of 320 ° C. to a resin thickness of 32 m at a running speed of the base paper of 150 mZ. In addition, the front and back The melt-extrusion coating of the resin was performed by a so-called tandem method in which the extrusion coating was performed sequentially. At this time, the surface of the second resin layer containing the titanium dioxide pigment of the resin-coated paper was processed into a glossy surface, and the surface quality of the first resin layer was processed into a mat surface such as paper.

Furthermore, after the corona discharge treatment on the first resin layer surface of the resin-coated paper, the following back coat coating liquid was applied on-machine. As dry weight, it is composed of colloidal silica: styrene-based latex = 1: 1 force, and polystyrene sulfonate soda 0 . 0 2 1 g Z m latte click scan min the bus click co one preparative coating solution containing other suitable amount of coating aid, etc. ² (in solid weight calculation) and to 0. 2 1 m ² to become the coating In this manner, an image material support was obtained.

 As described above, the molding processability of the polyethylene resin composition for the first resin layer, the degree of generation of gel-like foreign matter, and the obtained sample when producing the support for image materials are as described above. As a method for evaluating the performance as a support for an image material, the following method was used.

As a method for evaluating the moldability of the polyethylene resin composition of the first resin layer during the production of the support for imaging materials, the length of the resin-coated portion on the back surface in the horizontal direction is measured. In addition to assessing the degree of hot water, the degree of streaking of the molten resin film, the presence or absence of film breakage due to the degree of drawdown, anxiety of flow due to servicing or draw resonance Comprehensive evaluations were made of moldability such as qualitative properties. As evaluation criteria : 〇: good, △: slightly bad, but practically no problem,

X: Bad, indicates some degree of practical problem.

As a method for evaluating the gel-like foreign matter at the time of melting and extruding the polyethylene resin composition for the first resin layer, a set temperature of 320 ° C and an hour 2.5 in 0.0 1 off I in Lum in m ² after leaving press to 8 hours full I Le beam shaped under conditions of a kg

The gel-like foreign material was evaluated by measuring the number of gel-like foreign materials of 0.1 dragon or more and comparing it with the initial value. The evaluation criteria were as follows: ：: The number of gel-like foreign substances after 8 hours did not change from the initial value, Δ: The number of gel-like foreign substances after 8 hours increased slightly, but there was a practical problem. To some extent, X: After 8 hours, the number of gel-like contaminants increased significantly from the initial value, indicating that there was some practical problem.

 As a method of evaluating the cutting property of the support for image materials, the above-mentioned color photographic paper is subjected to a longitudinal print force with a longitudinal force of 11.7 cm. And the condition of the cut surface was evaluated. The evaluation criteria are: ：: hardly any whiskers are generated and extremely good cutting performance, 良好: little whiskers are generated, but good cutting performance, Δ: whisker generation Slightly large, but to the extent that there is no practical problem. X: Severe generation of whiskers, poor cutting properties, and some practical problems.

The curl properties of the image material support were evaluated in the following manner. First, a blue-sensitive emulsion layer containing a yellow color coupler after corona discharge treatment on the surface of the second resin containing the titanium dioxide pigment of the support for the image material, and a color-mixing inhibitor By providing an intermediate layer, a green-sensitive emulsion layer containing a magenta coloring coupler, an ultraviolet absorbing layer containing an ultraviolet absorber, a red-sensitive emulsion layer containing a cyan coloring coupler, and a protective layer, the total amount of gelatin is 8 have created a Color Camera photographic paper is a g Roh m ^2. Each color-sensitive emulsion layer comprises a silver chlorobromide corresponding to 0. 6 g / m ² in nitric acid and silver, further generation of of silver halide, other gelatin required dispersion and film formation, an appropriate amount of capsules Li Contains inhibitors, sensitizing dyes, coating aids, hardeners, thickeners, and appropriate amounts of filter dyes. Next, the prepared color photographic paper was stored at 35 ° (5 days at normal humidity), and after color development, the color photographic paper was 8.2 cm x i 1.7 cm at 40% RH. The condition of the curl of the color print was evaluated as follows: 〇: Slightly negative curl (curl toward the back coat layer side) Good curl physical properties, △: Curled, but not practically problematic, X: Large curl, practically problematic, _c As a method for evaluating the adhesiveness of a sample, each sample was stored at 50% in a 60% RH constant temperature and humidity chamber for one day, and then separated from the base paper layer of the sample and the resin layer on the back surface. The adhesiveness between the base paper and the backing resin layer was evaluated by measuring the area ratio of the base paper layer adhered to the separated resin layer. 〇: Area ratio of 100% is good, and △: Area ratio of less than 100% is 80% or more, and adhesion is slightly poor but there is no practical problem. X: Area ratio Is less than 80%, indicating that the adhesion is poor and there is some practical problem. The results obtained are shown in Table 10.

Table 10

(X): Gel-like difficulty from the beginning

Table 11

MFR density good 1.5 million

 Percentage of resin species

(g / 10 min) (g / cm ³ ) (heavy halo%) (1 / sec)

1 HD 15 0.967 ― 60

2HD 20 0.967 70 High density polyethylene 3HD 7 0.967 27 麵 (HDPE) 4HD 20 0.960 70

 5HD 28 0.967 _ 80

6HD 38 0.967 ― 80 or more

7HD 45 0.967 80

1 1 d 0.6 0.924 15.0 0.06

21 d 0.9 0.924 13.9 0.20 Low density polyethylene 31 d 1.2 0.924 13.4 0.36 views (DPE) 41 d 1.2 0.918 15.6 0.53

 51 d 3.5 0.926 9.1 1.6

61 d 0.8 0.923 4.1 1.5

71 d 0.4 0.923 9.2 0.32

Note that (Note 1) and (Note 2) in Table 10 are as follows.

-3

 (Note 1) Regarding pulp after beating JP A P A N T A P P I Paper pulp test method Nd 52-8 9 Length-weighted average fiber length measured in accordance with `` Paper and pulp fiber length test method ''

(mm). Measurements were taken with a Kajaani FS-100 model.

 (Note 2) Indicates the film thickness unevenness index R py (mV) of the base paper measured by the method specified in the main text.

 From the results shown in Table 10, the paper surface having the film thickness unevenness index Rpy of 140 mV or less was used as a substrate, and the base paper surface opposite to the side on which the image forming layer was provided was the high-density polymer according to the present invention. An imaging material support (sample No. 1) coated with a resin composition consisting of a specific compound resin prepared by melting and mixing a polyethylene resin and a low-density polyethylene resin in advance. , No. 2, No. 5, No. 9, No. 12, 1α 15, Να 18 and Nc 22) have good moldability of the resin composition, An excellent support for an image material which is free from generation, has a remarkably improved cutability of the support for the image material, and has good curl properties and good adhesion between the base paper and the first resin layer. It is easy to see that In particular, from the viewpoint of the cutting properties of the support for image materials, the base paper preferably has a thickness unevenness index R py of 135 mV or less, and 13 OmV or less. You can see that things are even better.

On the other hand, the film thickness unevenness index Rpy of the base paper is larger than 14 OmV. In a severe case (Sample No. 23), the cutting ability of the support for the imaging material is poor, which is a problem. When the critical shear rate is greater than 10 (1 nosec) as the resin composition for coating the backside of the base paper, a resin composition composed of a compound resin (3BL) is used ( Samples Να3, No.7, No.10, No.13, Να16 and No.20) have a lot of gel-like foreign matter, which is problematic and When a resin composition consisting of a compound resin (4BL) containing less than 65 parts by weight of ethylene resin is used (samples No. 4, No. 8, No. 11 and o 14, No. 17 and Να 21) have problems with poor curl properties. In addition, as a method of preparing the resin composition, when the resin composition is simply mixed (Sample No. 5), the moldability and cutting property of the resin composition are poor, and the generation of gel-like foreign matter from the initial stage. Many problems.

Example 3 3

 Instead of the pellets of the polyethylene resin composition for the back coating used in the sample Not 5 of Example 32, the amount of the high-density polyethylene resin (Table 12) was used. Preliminary melting of 1HD in Table 11) and low-density polyethylene resin (11d in Table 11) in the amount described in Table 12 using a kneading extruder. A compound prepared by mixing and having a critical shear rate as shown in Table 12 below. The procedure was performed in the same manner as in Sample No. 5 of Example 32, except that a pellet of a polyethylene resin composition composed of a resin was used.

Table 12 shows the obtained results. Table 1 2 Compound for the first fat layer Gel cut for the 1st shelf layer for the 1st column and the m ^ (haze) Compound tree Polyethylene tree Difficult to curl 1st layer

No.'s family name Crane with physical properties High-density polye Low-density polye Workability of releasable

24 95 5 30 X X X 〇 X

25 90 10 10 △ Δ Δ 〇 Δ

26 85 15 6.2 〇 〇 〇 〇 〇

27 80 20 4.4 〇 〇 ◎ 〇 〇

28 70 30 2.8 〇 ◎ ◎ 〇 〇

29 65 35 2.2 〇 〇 ◎ Δ 〇

30 50 50 1.0 〇 〇 ◎ X 〇

From the results in Table 11, the criticality was prepared by previously melting and mixing 90 to 65 parts by weight of high-density polyethylene resin and 10 to 35 parts by weight of low-density polyethylene resin. The imaging material support (samples Να 25 to Να 29) of the present invention in which the base paper is coated with a resin composition composed of a compound resin having a shear rate of 10 (1 Z second) or less is used. In addition, the resin composition has good molding processability, no gel-like foreign matter is generated, and the cutability of the support for the image material is good. 1 It is clearly seen that this is an excellent support for image materials having good adhesion to the resin layer. In particular, from the overall performance of the support for imaging materials, the content of the high-density polyethylene resin in the compound resin is preferably in the range of 85 to 70 parts by weight. It is well understood that the range of 80 to 70 parts by weight is more preferable from the viewpoint of the cutting property of the material support.

 On the other hand, when the content of the high-density polyethylene resin is more than 90 parts by weight (Sample No. 24), the moldability of the polyethylene resin composition is poor, and Gel-like contaminants are often generated, and the cutting properties of the support for the image material and the cutting properties between the base paper and the first resin layer are poor, which is a problem, and contains high-density polyethylene resin. If the amount is less than 65 parts by weight (sample Να30), the curl properties are poor, which is a problem.

Example 3 4

The samples of Example 32 were replaced with the pellets of the polylene resin composition for backside coating used in Example 5 (λ5). A pellet of a polyethylene resin composition composed of the same resin as the sample No. 5 of Example 32 using the polyethylene resin in the formulation shown in Table 13 is used. Except for the above, the procedure was the same as for sample # α5 in Example 32.

Table 13 shows the obtained results.

Table 13

The results in Table 13 show that the polyethylene resin composition for the first resin layer has an MFR force of '10 to 40 g / 10 minutes, and a density of 0.96 g / cm or more. there dense potentiation re ethylene les down resin 9 0-6 5 parts by weight and MFR of 0. 2 ~ 2 gZ 1 0 min, a density of 0. 9 ³ 5 gZcm 3 below, molecular weight 5 0 10,000 or more the fraction is 1 A compound prepared by previously melting and mixing 10 to 35 parts by weight of a low-density polyethylene resin having a critical shear rate of 0.5% by weight or less and a critical shear rate of 0.5% or less (1Z seconds) or less. Material (Polyethylene resin composition) comprising a resin (sample # α31) having a critical shear rate of 10 (1 Z seconds) or less. To 4α41), the molding processability of the polyethylene resin composition is good, no gel-like foreign matter is generated, and the cutting property of the support for the image material is good. Curl physical properties and base paper Adhesion between the first resin layer is excellent image material support is good this Togayo Ku seen.

In particular, as a low-density polyethylene resin for a compound resin, a resin having an MFR of less than 1 gZ10 minutes is preferable from the viewpoint of preventing the generation of a gel-like foreign substance. (Comparison of sample No. 32 and sample No. 38 with sample No. 39). As the high-density polyethylene resin for the compound resin, a resin having a density of 0.962 gZ cm ³ or more is preferred from the viewpoint of curl physical properties (sample No. Comparison between 32 and Not36 and sample # α37), the moldability of the polyethylene resin composition, the effect of preventing gel-like foreign matter, and the adhesion between the base paper and the first resin layer From the perspective of sex, its MFR power A sample in the range of 10 to 30 gZ l 0 min is preferable (sample Να

32, No. 36, and a comparison between No. 40 and No. 41). Further, it is preferable that the compound resin has a critical shear rate lower than 8 (1 Z second) (samples Να31 to Να38, Να40 and sample Να39). And comparison with No. 41).

 On the other hand, when the MFR of the low-density polyethylene resin for the compound resin is larger than 2 g / 10 minutes (Sample No. 44), the polyethylene resin composition This is a problem because the moldability and the degree of generation of gel-like foreign matter are poor, and the fraction of a low-density polyethylene resin for a compound resin having a molecular weight of 500,000 or more is 100,000. % By weight (Sample No. 43 to Να

In the case of 46), the moldability of the polyethylene resin composition is poor, which is a problem, and the generation of gel-like foreign matter tends to increase. When the MFR of the high-density polyethylene resin for the compound resin is greater than 40 gZl0 min (sample no.

The problem of 48) is that the molding processability of the polyethylene resin composition, the degree of generation of gel-like foreign matter, and the adhesion between the base paper and the first resin layer are poor. When the critical shear rate of the compound resin composition is larger than 10 (1 Z seconds) (samples 試 α42 to Να45 and Να48), gel-like foreign matter is generated. There are many problems.

According to the present invention, no gel-like foreign matter is generated in the resin layer on the side opposite to the side on which the image forming layer is provided, and the cutability is remarkably good. The resin layer with paper It is possible to provide an excellent resin-coated paper-type image material support that has good adhesiveness with the resin, can be produced at high speed, and can be produced stably.

Example 3 5

MFR 1 5.08 1 0 | 1 ^ 11, density 0.96 7 gZcm ³ 70 parts by weight of high-density polyethylene and MFR 0.6 g / 10 min, density 0.92 4 g / cm ³ , molecular weight of 500,000 or more, 15% by weight, critical shear rate: 0.06 (1 Z second) Low-density polyethylene: 30 parts by weight This was extruded on a highly smooth paper having a basis weight of 170 gZm ^{2 by} an extruder at a resin temperature of 320 ° C. so as to have a thickness of 25 / m by extrusion coating.

 As a method for evaluating the moldability during melt extrusion coating of the resin, the length of the resin-coated portion in the horizontal direction is measured to evaluate the degree of neck-in, and the line of the molten resin film is evaluated. Molding processability was evaluated comprehensively, including the degree of occurrence, the presence or absence of film breakage due to the degree of drawdown, and instability of flow due to surge or draw resonance. The evaluation criteria are as follows: ：: good, △: slightly bad, but no practical problem, X: poor, practical to some extent.

As a method of evaluating the adhesiveness between the base paper and the resin layer of the polyethylene-based resin-coated paper, the sample is separated into the base paper layer and the polyethylene layer, and the separated polyethylene is used. The adhesiveness between the base paper and the resin layer was evaluated by measuring the area ratio of the base paper layer adhered to the lens layer. Evaluation criteria are as follows:: Area ratio is 100% Good: Δ: Area ratio is less than 100% and is 80% or more. Adhesion is slightly poor but there is no practical problem. X: Area ratio is less than 80% and adhesion is good. Represents to the extent that there is a bad practical problem.

Evaluation methods for gel during resin melt extrusion include screw rotation speed, breaker plate opening ratio, and total number of screen pack meshes. The film was extruded for 8 hours under the condition of a set temperature of 320 and an extrusion rate of 2.5 kg per hour for 0.08 hours after the film was extruded. Ri by the and this is compared with 0. 1 mm or more measured initial value the number of gels in full I in Lum in m ^2, and and gel. Evaluation criteria: 〇: The number of gels after 8 hours does not change from the initial value. X: The number of gels after 8 hours increased from the initial value.

 As a method for evaluating the secondary workability of a polyethylene-based resin-coated paper, the cutability of a cut sample obtained by cutting a sample with a commercially available guillotine cutter was evaluated based on the degree of fluffing. When the resin layer surfaces of the coated paper were overlapped and rubbed with each other, the abrasion resistance depending on the degree of scratch on the resin layer surface and the secondary workability such as the stiffness of the resin coated paper were comprehensively evaluated. The evaluation criteria are as follows: 〇: good, △: somewhat bad but not practically problematic, X: poor and somewhat practically problematic.

Example 3 6 to 4 1

The procedure was the same as in Example 35, except that the polyethylene resin composition was changed to the resin types and proportions shown in Tables 14 and 15. Table 14

MFR density good 1.5 million

 Hanging HS

g / 10 min g / cm ³ chapter halo 1 / sec High density polyethylene A 15 0.967 60

(HDPE) B 20 0.960 70

C 7 0.967 27 Low density polyethylene d 0.6 0.924 15.0 0.06

(LDPE) e 1.2 0.918 15.6 0.53 f 3.5 0.926 9.1 1.6

The results obtained are shown in Table 15 and Table 16.

Table 15

HDPE LDPE SCREEN BRAKE CARBRATE SCREEN BANK 7k

Opening rate of sample fiber 繊 搠 圧 圧 搠 搠 搠 搠 比 搠 比 搠

Dummy part Army part 1 / sec rpm% kgf / cm ² kgf / cm ² examples 35 A 70 d 30 2.3 35 40 500 12 6 examples 36 A 75 d 25 3.1 35 40 1000 20 12 examples 37 B 80 e 20 17.0 35 10 1000 26 25 Example 38 B 80 e 20 17.0 60 10 500 37 20

Example 39 B 80 e 20 17.0 35 40 500 7.25 Example 40 A 97 d 3 40.0 60 10 1000 16 18 Example 41 C 65 f 35 5.2 35 40 500 15 14

Table 16

From the results in Table 15, it can be seen from the results that the resin pressure at the extruder screw tip is higher than the critical resin pressure by melt extrusion conditions. Polyethylene resin-coated paper (Examples 35 to 38) ) Clearly shows that it is an excellent polyethylene-based resin-coated paper that does not generate gel and has good moldability and good adhesion between the resin layer and the base paper. In particular, even when the rotational speed is low, even when the resin pressure is equal to or higher than the critical resin pressure (Example 37), it is clear that no gel is generated.

On the other hand, if the resin pressure at the tip of the screw of the extruder is lower than the critical resin pressure (Examples 39 and 40), the gel is bad and a problem. When the content of the high-density polyethylene is more than 90 parts by weight (Example 40), the adhesiveness between the gel and the base paper and the resin layer and the formability are poor, which is a problem. Also, if the MFR of high-density polyethylene is smaller than 10 g In this case (Example 41), secondary workability is poor and a problem.

 ADVANTAGE OF THE INVENTION According to the present invention, the resin layer is excellent in moldability, the adhesiveness between the resin layer and the base paper is good, and the resin layer can be prevented from gelling. Can supply ren-based resin coated paper.

Example 4 2

A mixture of bleached hardwood pulp and hardwood bleached kraft pulp 1: 1. The pulp is beaten to 320 ml of canadian standard freeness, and 100 parts by weight of the pulp is further reduced to 3 parts by weight of carotinized starch and anion. Polyacrylamide 0.2 parts by weight, alkyl ketene dimer emulsion (as ketene dimer) 0.4 part by weight, polyaminopolyamide b Norre arsenide drill down resin 0.4 parts by weight added pressure were making paper having a basis weight of 1 6 0 gZ ni ^2. The obtained wet paper was dried at 110 ° C., and subsequently 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 part by weight of fluorescent whitening agent, 0.05 part by weight of blue dye 0.000 2 parts by weight, Na Application Benefits U arm 4 parts by weight chloride, click E phosphate 0.2 parts by weight of water 9 3 parts by weight or et consisting impregnating solution 2 5 gZ m ² impregnated, the finally obtained base paper The film was dried with hot air so that the water content would be 8% with absolutely dry water, and then subjected to super force rendering at a linear pressure of 90 kg / cm to produce a base paper as a support for image materials. The Beck smoothness of the base paper at this time was 200 seconds.

Next, the base paper surface (back surface) opposite to the side on which the image forming layer is coated is subjected to a corona discharge treatment, and the back surface is described in Table 17 below. The polystyrene resin composition was melt-extruded and coated at a resin temperature of 320 ° C. to a resin thickness of 25 / m at a running speed of the base paper of 150 mZ. At this time, as the cooling roll, one having a center surface average roughness SRa of the first resin layer surface having the roughness shown in Table 17 was used. The cooling port used was a cooling roller roughened by the liquid honing method, and operation was performed at a cooling water temperature of 12 using this cooling roller.

Subsequently, after the surface of the base paper was subjected to corona discharge treatment, a low-density polyethylene resin (density 0.920 g / cm ³ , MFR = 8.5 g / 10 minutes) was applied to the surface. 7.5 wt%, a 1 ₂ 0 ₃ minutes and to 0.7 5 surface-treated with weight analysts evening one peptidase type two titanium oxide emissions Pigments 5 0 for hydrated Aluminum Niumu (vs. titanium dioxide emissions 20 parts by weight of a titanium dioxide pigment master batch consisting of 2.5% by weight of zinc stearate and 2.5% by weight of zinc stearate, low-density polyethylene resin (density 0.920 g / cm ³ , MFR = 4.5 g / 10 min) 65 parts by weight and high-density polyethylene resin (density 0.970 g / cm ^3. MFR = 7.0 gZO min) 15 The resin composition consisting of the weight parts was melt-extruded and coated at a resin temperature of 320 to a resin thickness of 32 m at a running speed of the base paper of 150 mZ. Melt extrusion coating of polyethylene resin The next extrusion coating was performed in a so-called tandem method, in which case the surface of the second resin layer containing the titanium dioxide pigment of the resin-coated paper was entirely covered with a gasket. Processed to.

Furthermore, after the corona discharge treatment, the surface of the first resin layer of the resin-coated paper is The following back coat coating solution was applied on machine. As dry weight, colloidal silica: Styrene latex

= 1:. 1 Kaka RaNaru is, further Po Li styrene Les emission scan Honoré off O phosphate soda 0 0 Ba click co one preparative coating comprising 2 1 Other suitable amount of coating aid of g / m ^2, etc. The liquid was applied at a coating amount of 0.21 g / πι ² as a latex content (calculated on solid weight) to obtain a support for an image material.

 As described above, the moldability of the polyethylene resin composition for the first resin layer, the degree of generation of cooling roll stains, and the generation of gel-like foreign matter when the support for image materials is manufactured as described above The degree and the method of evaluating the performance of the obtained sample as a support for image materials were evaluated by the methods described below.

 As a method for evaluating the moldability of the polyethylene resin composition for the first resin layer at the time of manufacturing the support for the image material, the lateral length of the resin-coated portion on the back surface is measured. In addition to evaluating the degree of neck-in, the degree of streaking of the molten resin film, the presence or absence of film breakage due to the degree of drawdown, the flow due to surge or draw resonance Formability such as instability was evaluated comprehensively. The evaluation criteria are as follows: ：: good, △: somewhat bad, but no practical problem: poor, with some practical problems.

As a method for evaluating the contamination of the cooling roll when the polyethylene resin composition for the first resin layer is melt-extruded, the cooling is performed 6 hours after the start of the production of the image material under the production conditions described above. The occurrence of dirt on the roll was visually judged and evaluated, The evaluation criteria were as follows: 〇: Good with little generation of dirt on the cooling roll, Slightly high generation of dirt on the cooling roll, but to the extent that there is no practical problem. Represents to some extent a practical problem.

As a method for evaluating the gel-like foreign matter at the time of melt-extrusion of the polyethylene resin composition for the first resin layer, a set temperature of 320 ° C. 2.5 per hour 2.5 0 after leaving press to 8 hours full I le厶状under conditions of a kg. 0 0 in 1 m ² of the full I le厶中. 1 mm or more gel-like number of foreign matter was measured early in Gel-like foreign substances were evaluated by comparing the values with the values. The evaluation criteria were as follows: ：: The number of gel-like foreign substances after 8 hours did not change from the initial value, Δ: The number of gel-like foreign substances after 8 hours increased slightly, but there was a practical problem. To some extent, X: After 8 hours, the number of gel-like contaminants increased significantly from the initial value, indicating that there was some practical problem.

 As a method for evaluating the cutting property of the image material support, the above-mentioned color photographic paper is subjected to a longitudinal print force of 11.7 cm with a longitudinal print cutter. It was cut into pieces as required, and the condition of the cut surface was evaluated. The evaluation criteria are as follows: ◎: Almost no whiskers are generated, and the cutting performance is extremely good. 〇: There is a slight whisker generation, but the cutting performance is good. Δ: Slight whiskers are generated. There are many, but to the extent that there is no practical problem. X: There are many mustaches, poor cutting properties, and there is a practical problem to some extent.

The curl properties of the image material support were evaluated in the following manner. First, the support for the image material After a corona discharge treatment on the surface of the second resin layer containing the titanium oxide pigment, a blue-sensitive emulsion layer containing a yellow color coupler, an intermediate layer containing a color-mixing inhibitor, a green-sensitive emulsion layer containing a magenta evening color coupler, A color photographic paper having a total amount of gelatin of 8 g Zm ² was prepared by providing an ultraviolet absorbing layer containing an ultraviolet absorber, a red-sensitive emulsion layer containing a cyan-coloring coupler, and a protective layer. Each color-sensitive emulsion layer comprises a silver chlorobromide corresponding to 0. 6 g / m ² with silver nitrate, further c b generation of gain down and silver, other suitable amount of coupler Li of Zerah Chi emissions required dispersion and deposition Contains inhibitors, sensitizing dyes, coating aids, hardeners, thickeners, and appropriate amounts of filter dyes. Next, the prepared color photographic paper was stored at 35 ° C and normal humidity for 5 days, and then developed at 20 ° C and 40% RH at 20 ° C after color development. Curl prints of cm-size color prints were evaluated. The evaluation criteria are as follows: ：: Slightly negative curl (curl to the back coat layer side) or flat, good curl physical properties, △: Curled, but practically problematic Degree of absence X: The scale is large and presents some problems in practical use. The evaluation method of the adhesion between the base paper of the support for image material and the first resin layer is as follows. After storing for 1 day in a 50% and 60% RH constant temperature and humidity chamber, the sample is separated from the base paper layer and the first resin layer, and the area ratio of the base paper layer adhered to the separated resin layer is measured. By doing so, the adhesiveness between the base paper and the back resin layer was evaluated. Evaluation criteria are as follows: ：: 100% area ratio is good. △: 80% or more when area ratio is less than 100%. Adhesion is slightly poor, but there is no practical problem. , X: area ratio is 80 %, The degree of adhesion is poor and there is some practical problem.

The results obtained are shown in Table 17.

Table 17

(X): Gel-like difficulty from the beginning ^ ^;

(Note 1) HDPE: density ^{0. 9 6 7 g / cm 3} , MFR = 1 5 gZ 1 0 minute dense potentiation Re ethylene les down resin.

(Note 2) LDPE: Density 0.92 4 gZcm ³ , MFR =

Low-density polyethylene resin with 0.6 g / 10 min, fraction with a molecular weight of 500,000 or more = 15% by weight Critical shear rate = 0.06 (1 Z second).

 (Note 3) Preparation method of polyethylene resin composition-compound: A resin resin prepared by previously melting and mixing HDPE and LDPE using a kneading extruder. Used as a let. Simple mixing: HDPE and LDPE were added to a melt extruder as they were in simple mixing. (Note 4) Indicates the average roughness SRa (um) of the center surface of the first resin layer surface of the support for image materials, measured by the method specified in the specification.

From the results shown in Table 17, the average roughness SRa of the center surface of the first resin layer surface is 0.6 to 2.0 μm, and the polyethylene resin in the first resin layer is the present invention. 90 to 65 parts by weight of the high-density polyethylene resin and 10 to 35 parts by weight of the low-density polyethylene resin in The support for imaging materials (samples No. 2, No. 3, Nos. 5 to 9α9 and 12), which is a resin, has good molding processability of the polyethylene resin composition. Excellent image material support that does not generate cooling roll stains, generates no gel-like foreign matter, and has good adhesiveness between base paper and resin layer, curl physical properties and cutability. It is easy to see that In particular, From the viewpoint of the overall performance of the support for image materials, the content of HDPE is preferably in the range of 85 to 70 parts by weight, and from the viewpoint of the effect of improving the cooling roll stains, As the average roughness SRa of the center surface of the backing resin layer surface of the support for the substrate, a range of 0.8 to 1.6 μm is preferable.

 On the other hand, when the content of the high-density polyethylene resin is more than 90 parts by weight (Sample No. 1), the molding processability of the polyethylene resin composition is poor and the cooling roll There are many problems such as generation of dirt, generation of gel-like foreign matter, and poor adhesion and cutting properties between the base paper and resin, and high-density polyethylene resin. If the content is less than 65 parts by weight (Sample No. 13), the curl properties are poor and there is a problem. When the polyethylene resin composition is simply mixed (sample 11), the molding processability and cutting property of the polyethylene resin composition are poor. From the beginning, gel-like foreign matter is often generated, which is a problem. Further, when the average roughness SRa of the center surface of the first resin layer surface is smaller than 0.6 μm (sample Να4), there is a problem because the cooling roll is more contaminated. When the average roughness of the center plane SRa is larger than 2.0 m (Sample 10), the cooling hole is still dirty, which is a problem. After the material support was wound up, there was also a problem that the front side mirror surface was fogged everywhere.

Example 4 3

Example 4 Polyurethane for back coating used in sample No. 7 of 2 Instead of the ren resin composition, a compound prepared in the same manner as in Sample No. 7 of Example 42 using the polyethylene resin shown in Table 18 and the formulation shown in Table 19 The procedure was performed in the same manner as in Sample # α7 of Example 42, except that the resin was used as a resin composition.

Table 18

MFR density liver 1.5 million

 Resin type More fraction

(g / 10 ^{min) (g / cm 3) (} 1 / sec)

A 15 0.967 ― 60

B 20 0.967 70 卨 High density polyethylene C 7 0.967 27 櫬 (HDPE) D 20 0.960 70

 E 28 0.967 80 or more

F 38 0.967 80 or more

G 45 0.967 80 or more h 0.6 0.924 15.0 0.06 i 0.9 0.924 13.9 0.20 Low density polyethylene j 1.2 0.924 13.4 0.36 Column (LDPE) k 1.2 0.918 15.6 0.53

1 3.5 0.926 9.1 1.6 m 0.8 0.923 4.1 1.5 n 0.4 0.923 9.2 0.32

Table 19 shows the obtained results.

Table 19

From the results in Table 19, the polyethylene resin in the first resin layer was found to have an MFR force of 10% / 10 minutes to 40 g / 10 minutes, and a density of 0.960 g / cm ³ 90 parts by weight to 65 parts by weight of high density polyethylene resin! ^ 1? 1¾ is 0. 2 gZ l O min ~ 2 g / 1 0 min, a density of 0. 9 ³ 5 g / cm 3 or less, molecular weight 5 0 10,000 or more in fraction 1 0 wt% or more, critical shear A low-density polyethylene resin having a speed of 0.5 (1 Z seconds) or less is a compound resin composition prepared by previously melting and mixing 10 to 35 parts by weight of a low-density polyethylene resin. The support for an imaging material (sample # α14 to No. 24), in which the composition has a critical shear rate of 10 (1 Z seconds) or less, is formed by molding a polyethylene resin composition. Good addition properties, no chill roll contamination, no gel-like foreign matter, good adhesion between base paper and resin layer, good curl properties and good cutability It can be clearly seen that this is a support for image materials.

In particular, as the low-density polyethylene resin, those having an MFR of less than 1 gZ10 minutes are preferred from the viewpoint of preventing the generation of gel-like foreign substances (Sample No. 15 and Να). 21 and Sample No. 22). As the high-density polyethylene resin, those having a density of 0.962 gZ cm ³ or more are preferable from the viewpoint of the physical properties of the sample (Samples 15 and 19). And the sample α20), and from the viewpoints of moldability, the effect of preventing gel-like foreign matter, and the adhesion between the base paper and the resin layer, the MFR is 10 g / 10 minutes to 30 minutes. g / 10 min is preferred (Sample No. 15, 、 α 19 And 比較 α23 vs. No.24). Further, as the compound resin composition used in the practice of the present invention, those having a critical shear rate lower than 8 (1 Z seconds) are preferable (samples Ναΐ4 to Να21 And Να23 with the samples Να22 and Να24).

 On the other hand, when the MFR of the low-density polyethylene resin is larger than 2 g / 10 minutes (Sample No. 27), the moldability and the degree of generation of gel-like foreign matter are poor, which is a problem. On the other hand, if the low-density polyethylene resin has a molecular weight of 500,000 or more and a fraction of less than 10% by weight (samples Na27 to Nd29), the moldability is poor. This is problematic, and the generation of gel-like foreign matter tends to increase. When the MFR force of the high-density polyethylene resin is greater than 40 g Z 10 min (Sample Not 31), the moldability, the degree of gel-like foreign matter generation, and the base paper and resin layer This is a problem due to poor adhesion to the adhesive. When the critical shear rate of the compound resin composition is greater than 10 (1 Z seconds) (samples Να25 to Να28 and Να31), gel-like foreign matter is not generated. This is a problem, and there is a tendency that the occurrence of contamination of the cooling roll is increased.

ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of a chill roll stain during production is small, therefore, there is no problem by transfer of a chill roll stain, and gel is formed in the resin layer opposite to the image formation layer side. No foreign matter in the form of a solid, good adhesion between the resin layer and the base paper, good curl physical properties and cuttability, high-speed production, and stable production. An excellent resin-coated paper type image material support can be provided.

Claims

The scope of the claims

1. In a resin-coated paper comprising a paper substrate and a first resin layer provided on one surface of the paper substrate, the first resin layer is formed of a metal flow defined by JISK6706. -1.0 g / 10 min to 40.0 gZ 10 min, high-density polyethylene resin with a density of 0.960 gZcm ³ or more 90 parts by weight to 65 parts by weight parts and, JISK 6 7 6 0 is the main le walk b Moltrasio over preparative is 0. 2 g / 1 0 min to 2/1 0 min defined by, density is 0. 9 ³ 5 gZcm 3 or less, the molecular weight 10% by weight or less of low-density polyethylene resin or medium-density polyethylene resin with a ratio of 500,000 or more at 10% by weight or more and a critical shear rate of 0.5 (1Z second) or less A resin coating comprising a polyethylene resin composition obtained by melt mixing 35 parts by weight with a resin composition having a critical shear rate of 10 (1 Z second) or less. paper.

2. The low density po Re ethylene les down or claims intermediate density Po Li E Ji les down the main Honoré walk opening one rate is 0.2 8 / ^/ 1 0 min ~ 1 gZ l O min 2. The resin-coated paper according to item 1.

 3. The average longitudinal roughness SR a of the first resin layer measured with a stylus-type three-dimensional surface roughness meter at a cut-off value of 0.8 mm is 0.6 to 2. 2. The resin-coated paper according to claim 1, which has a length of 0 m.

4. A second resin layer made of a film-forming resin is provided on the surface of the paper base opposite to the surface on which the first resin layer is provided. The resin-coated paper according to claim 1, wherein the paper is coated.

5. The resin-coated paper according to claim 4, wherein a thickness unevenness index R py in the papermaking direction of the surface of the paper substrate on which the second resin layer is provided is 14 OmV or less.

 6. The resin-coated paper according to claim 4, wherein the image forming layer is provided on the second resin layer.

 7. The resin-coated paper according to claim 6, wherein said image forming layer is a silver halide photographic constituent layer.

8. resin-coated paper according to paragraph 4 scope of coverage of the resin of the second resin layer is first tree fat resin layer coverage by Ri 3 GZcm ² or more claims.

 9. The resin-coated paper according to claim 4, wherein the second resin layer contains a titanium dioxide pigment.

 10. The resin-coated paper according to claim 4, wherein the resin capable of forming a film is a polyolefin resin.

 11. The resin-coated paper according to claim 10, wherein the polyolefin resin is a polyethylene resin.

12.When the mole flow rate specified by JISK 670 is 100.0 gZ 10 min to 40.0 g / 10 min, and the density is 0.96 gZcm ³ or more. 90 to 65 parts by weight of a certain high-density polyethylene resin and the melt flow rate specified in JISK 670 are 0.2 g / 10 minutes to 2 g / 1 0 min, a density of 0. 9 ³ 5 g / cm 3 or less, molecular weight 5 0 10,000 or more ratio of 1 0% by weight or more, low density port Li the critical shear rate is 0.5 (1 / sec) or less Ethylene resin or medium density A resin-coated paper comprising melt-extruding 10 parts by weight to 35 parts by weight of a polyethylene resin and extruding the polyethylene-based resin composition to coat on a paper substrate. A method for producing a resin-coated paper, wherein the melt-mixed resin composition has a critical shear rate of 10 (1 / sec) or less.

 13. The production method according to claim 12, wherein the resin pressure at the screw tip of the extruder is higher than the critical resin pressure, and the polyethylene resin is melt-extruded.

 14. Claims that melt extrude the polyethylene resin at a screw speed of the extruder at or above the critical speed.

12. The production method according to item 2.

 15. In a resin-coated paper comprising a paper substrate and a first resin layer provided on one surface of the paper substrate,

JISK 6 7 6 0 at defined the main Honoré walk opening one record over preparative force M. In 0 ~ 4 0 g / 1 0 min, density of 0. 9 3 0 ~ 0. 9 7 1 g Roh cm ³ A resin-coated paper having a critical shear rate of 20 (1 Z seconds) or less.

 16. The resin-coated paper according to claim 15, wherein the critical shear rate is 15 (1 Z seconds) or less.

 17. The method according to claim 15, wherein a second resin layer made of a film-forming resin is provided on a surface of the paper base opposite to the surface on which the first resin layer is provided. Resin coated paper.

 18. The resin-coated paper according to claim 17, wherein a surface image forming layer is provided on the second resin layer.

19. When the image forming layer is a silver halide photographic constituent layer, Item 18. The resin-coated paper according to Item 18.