DE4493152B4 - Resin coated paper - Google Patents

Abstract

A resin-coated paper comprising a paper substrate and a first resin layer formed on one side of the paper substrate, said first resin layer comprising a polyethylene-type resin obtainable by melt blending of 90 to 65 wt High density polyethylene resin of 0.960 g / cm ³ or more, which has a melt index according to JIS K 6760 of 10.0 to 40.0 g / 10 min, with 10 to 35 parts by weight of low or medium density polyethylene resin of 0.935 g / cm ³ or less, which has a melt index according to JIS K 6760 of 0.2 to 2 g / 10 min, a percentage of molecules having a molecular weight of 500,000 or more of 10 wt% or more, and a value for the critical shear rate of 0.5 s ^-1 or less, the composition obtained by the melt blending having a value of the critical shear rate of 10 s ^-1 or less.

Description

The The present invention relates to a resin-coated paper containing Paper as a substrate, a coating of a resin layer on one side of the paper substrate (hereafter referred to as "base paper"), followed by a layer to form an image, and optionally containing a coating from a resin layer on the other side of the base paper, wherein the former resin layer of a resin composition mainly of one Polyolefin resin and the latter resin layer of a resin composition mainly Polyethylene-type resins with the resin-coated paper for use as a carrier for a Material is suitable for forming an image. In particular, it concerns the present invention is a carrier pad of the type resin coated paper for a material for forming an image, the paper being free of Problems is caused by the transfer of Stains on a chill roll caused the paper has no gelatinous foreign matter, the in the resin layer forms on the side opposite to the Side on which the layer is applied to form an image should be, and where the papers performance characteristics such as curl properties, cuttability and adhesion between the base paper and the resin layer is good enough fulfill and can be produced quickly and stably.

There are already known resin-coated papers which can be obtained by coating at least one side of a base paper with a resin having film-forming properties, which are carrier bases for a material for forming an image. For example, JP 55-12584 B discloses a photographic technique relating to a photographic base, which base is obtainable by coating a base paper with a resin having film-forming properties, preferably a polyolefin resin. US Pat. No. 3,501,298 discloses a technical procedure relating to a photographic base, which base is obtainable by coating both sides of a base paper with a polyolefin resin. Since the introduction of a rapid photographic development process for a silver halide light-sensitive material, mainly photographic base materials prepared by covering both sides of a base paper with a polyethylene-type resin have been put to practical use, with the resin layer on one side of the base paper that is, the image-forming side, usually containing a titanium dioxide pigment for imparting precision if necessary.

Moreover, in US 4,774,224 a thermal transfer recording image-receiving member has been proposed which comprises, as a substrate, resin-coated paper having a surface roughness of the resin coating of 7.5 microinches-AA or less, particularly a polyethylene resin-coated paper obtained by coating the surface of a base paper with a polyethylene resin is. JP 63-307979 A discloses an ink jet printing technical sheet comprising resin-coated paper as a base.

Further, there have been proposed technical methods relating to photographic base materials obtained by coating base paper on the back side to the side on which a photographic layer is to be formed with a resin composition comprising a low-density polyethylene resin and a high-density polyethylene resin Contains density. For example, JP 44-22904 B discloses a photographic base obtained by coating base paper with a polyethylene composition containing 15 to 65% by weight of a specific low-density polyethylene resin having a density of 0.915 to 0.926 g / cm ³ and a density of 0.915 to 0.926 g / cm ³ Melt index of 2.9 to 16 g / 10 min and 85 to 35 wt.% Of a specific high density polyethylene resin having a density of 0.960 to 0.975 g / cm ³ and a melt index of 5 to 18 g / 10 min, the ability to has rapid coating formation and does not cause any beading or pinholes. JP 48-9963 B discloses a photographic base obtained by coating base paper with a resin composition comprising a low-density polyethylene resin and a high-density polyethylene resin in a ratio of 1: 1, which undercoat is satisfactory in curling property. Further, JP 58-95732 A discloses a photographic base obtained by coating base paper with a polyethylene resin composition containing 40 to 75 parts by weight of a high-density polyethylene resin having a density of 0.945 g / cm ³ or more and a melt index from 15 to 40 g / 10 min. and 60 to 25 parts by weight of a low density polyethylene resin having a density of 0.930 g / cm ³ or less and a melt index of 1 to 40 g / 10 min., the backing having cuttability and corrugation properties satisfactory fails.

However, it has been found that even by using each of these resin compositions comprising a low-density polyethylene resin and a high-density polyethylene resin, which have been disclosed in the prior art, a serious problem is caused in the production of a resin-coated paper-type support for a material for forming an image containing a substrate as a substrate paper. The resin-coated paper type of material for forming an image still has serious drawbacks in terms of quality.

in the one is, first, one coated with a polyethylene-type resin Usually through paper made a series of steps, wherein a resin composition from the molten polyethylene type to a running film Base paper extruded through the slot die of a melt extruder, pour the film onto the base paper to make the base paper with it to coat, the same under pressure with the base paper between a press roll and a chill roll connects, and the resulting structure of the rolls after cooling deducted. However, the previously known resin composition of a Polyethylene resin of low and high density used, tends the chill roll to, stains from mainly the polyethylene resin composition or a modified product of which are called "chill roll stains". The production of polyethylene resin coated paper is carried out by the melt extruder continuously at least two to three For days, usually one week, and sometimes a month, from the beginning of operation run leaves. there the following tendency has been observed: the longer the continuous operating time the more it heats up, the more it heats up the chill roll spots disadvantageously.

This has led to the following problem. Kick a big one Number of spots during production of polyethylene resin-coated paper the peel behavior of the polyethylene resin coated Paper from the chill roll, in particular, the adhesion between the cooling roll and the resin layer becomes elevated, what a stronger one Tendency of the resin layer for sticking to the cooling roller leads. As a result, the Adhesion between the base paper and the resin layer unevenly lowered and in the worst case, base paper and resin layer split from each other. Thus, the polyethylene resin coated Paper outwardly unsuitable, and as a resin-coated paper for a base for an image-forming material unsaleable. In addition, the following problem has occurred. The polyethylene resin coated Paper is wound up, with the accumulated chill roll spots on the Glue the resin layer, and thereby the stains are transferred, around on the resin layer surface to appear on the side on which a layer to education an image should be formed. This will be a quality deterioration causing fatal damage to the application of the resin-coated Paper as a pad for an image-forming material. In addition, caused in, in some cases, the problem of transmission the chill roll spots the following more serious problem: the spots are first on the roller of a laminator for the production of the resin-coated Paper or transferred to the roller of an emulsion coater and then retransfer for the quality to worsen. Therefore, it was necessary to take a suitable action too grab around the chill roll spots to prevent.

at Use of the heretofore known resin composition of a polyethylene resin secondly, there is a tendency for a low and high density gelatinous Foreign matter on the surface of the coating resin forms. The following tendency has emerged: the longer the continuous operation continues, the more the gelatinous foreign matter is formed disadvantageously.

starts the gelatinous Foreign matter during the production of the resin-coated paper is formed the following serious problem: The resins in the coating are thinned to Strips form, and in some cases breaks occur, so that no uniformly coated resin coated paper available is. With a carrier pad for a Educational material obtained by placing a page a base paper having a resin layer of a resin composition mainly a polyolefin resin and the other side of the base paper with a Resin layer of a resin composition of mainly one Polyethylene-type resin covers, deteriorates the presence of the gelatinous foreign matter in the coating resin layer on the back side to the side on which an image-forming layer is applied should be (the former and latter page are below in abbreviated As "the back" or "the front"), the Appearance of an image forming material comprising said backing to the commercial utility of the image-forming material to destroy. Becomes the gelatinous Foreign matter in the resin layer on the back (hereinafter abbreviated as "the back Resin layer "), In particular, the following problem arises: an image-forming layer, in particular a photographic layer of silver halide, on the resin layer on the front side (hereinafter abbreviated as "the front side Resin layer ") by coating trained, the coating becomes through influences disturbed, from the back originate, to fail unevenly, which leads to a fatal deterioration of quality. Therefore, it was necessary also to take appropriate action in this regard Formation of gelatinous To prevent foreign matter.

Out For this reason, the inventors have the cause of the formation of gelatinous foreign matter examined. Is to start with, base paper with melted Polyethylene-type resin coated by on extruding the molten resin, this process takes place at a temperature considerably higher than the melting point of the polyethylene type resin. For example, the melting points of a polyethylene resin low and high density at about 105 to 110 ° C and at about 120 to 130 ° C, whereas the temperature during melt extrusion through an extruder die at about 300 ° C to coat with a thin one Film must lie. It is known that in general polyethylene molecules, next to a linear carbon chain formed by a polymer Ethylene monomers is built up, unsaturated bonds such as carbon-carbon double bonds and carbon side chains through a carbon skeleton with methyl groups or groups higher Order are formed. The following relationship is given. A Temperature of about 300 ° C is suitable for Polyethylene from the viewpoint of working efficiency, but lies in one Area where activation accelerates at the molecular level is. Especially with longer ones Operating time weden then radicals in the neighborhood of the unsaturated Bonds and the carbon side chains are formed in the molecules, what factors like a change the fluidity of the molten Polyethylene-type resin conditions, and radicals go one Chain reaction. As a result, the molten resin goes from Polyethylene type a crosslinking reaction to within a Accumulate extruder and stay. In some cases occurs the reaction product as a gelatinous foreign matter and is extruded together with the film.

When measure for preventing the formation of such gelatinous foreign matter one can perform the process at a reduced extrusion temperature. In In this case, however, the adhesion between the polyethylene-type resin is and the paper deteriorates, so that the processing speed is limited to maintaining a necessary level of liability, which in turn leads to low productivity. Disassemble and clean the extruder at short intervals represents an effective measure However, productivity inevitably lowers. The study carried out by the inventors has produced that the incorporation of an antioxidant into the resin composition of Polyethylene type to some extent until prevention formation of gelatinous Foreign matter. However, this will be the following problem caused: the antioxidant must be added in large quantities, and in this case falls the adhesion between the base paper and the resin layer only very much insufficient out. In particular, resin-coated paper is subjected to high-speed conditions at a running speed of the base paper of 150 m / min or produces more, the problem becomes further deterioration the adhesion between the base paper and the resin layer caused.

thirdly must be resin-coated Paper as a backing for a Image forming material having excellent smoothness of the front surface resin. On the other hand, a carrier pad with a balance of standard requirements for one User re the texture, the feeling aimed at with the hand, the nerve and the like of an image-forming material. The most effective measure to improve the smoothness Resin-coated paper represents the increase in the coating weight of the front-side resin layer However, if the basis weight of the base paper is compared to increase the coating weight the front side resin layer is lowered, the above-mentioned texture, feel benefits significantly worsened with the hand, nerve and the like. Therefore it prefers a measure to choose, in which the coating weight the backside resin layer decreases. In this case, however, the following problem is caused: an image-forming material obtained by the use of the resin-coated Paper as a backing is obtained, curls toward the Harzzseite of image formation, so that his Handling becomes very difficult.

Therefore, the following measure is adopted: a resin layer mainly of a low-density polyethylene type resin is used as a resin composition for the back resin layer of a resin-coated paper-type support for an image forming material, and the density of the back resin layer is increased by: increasing the content of the high-density polyethylene type resin in the resin composition, thereby smoothing an image-forming material obtained by using the resin-coated paper as a support base by preventing its corrugation or curling a little toward the back side, and in particular, the corrugation properties of the image-forming material are improved. However, even in this case, the following problem is caused: in proportion as the content of the high-density polyethylene type resin in the resin composition is increased to, for example, 60% by weight or more, especially 70% by weight or more the cuttability of a resin-coated paper-type support for an image-forming material whose base is made by coating with the resin composition or the image-forming material having the base for the image-forming material is deteriorated. In detail will Also, the following problem is caused: the base for the image-forming material or the image-forming material having the base for the image-forming material is cut to a desired size with a cutter such as a guillotine cutter or a precision printing cutter whisker-like protrusions on the cut surface of the image forming material underlay to degrade the commercial value of use.

Also this causes the following problem: to the extent that the coating weight the back Resin layer of the resin-coated paper type base for the Imaging material is reduced, the adhesion deteriorates between base paper and the resin layer. This problem of liability weakening between the base paper and the resin layer will increase with a Circulation speed of the base paper even clearer.

To All this it is an object of the present invention, a carrier pad resin-coated paper type of material for formation to provide an image that is obtainable by using paper as a substrate and the front of this base paper with a resin composition mainly of a polyolefin resin and the back of the base paper having a resin composition of mainly resins of the polyethylene type, the carrier pad To mark as follows: in the process of production of these Support base hardly any chill roll spots form, so that no Problem is caused by their transmission could; it does not form gelatinous Foreign matter in the resin layer on the back to the side, on which a layer is applied to form an image should; after all becomes a carrier pad with fairly good performance characteristics, such as corrugation properties, Cuttability and adhesion strength between the back Resin layer and the base paper produced under production conditions, with the backing quickly and can be stably produced. Other items and Aspects of the present invention will become apparent from the following Description essay evident.

The Inventors have purposefully investigated to solve the above problems carried out, and consequently found that for use as a backing for a Material suitable for forming an image, desired resin-coated Paper available is by placing one side of the base paper with a resin layer made of a specific high-density polyethylene and one specific medium density polyethylene or a specific one Low density polyethylene.

More specifically, the present invention relates to resin-coated paper comprising a paper substrate and a first resin layer formed on one side of the paper substrate, said first resin layer comprising a polyethylene-type resin obtainable by mixing in the paper Melt of 90 to 65 parts by weight of high density polyethylene resin of 0.960 g / cm ³ or more, which has a melt index (hereinafter usually referred to as melt flow index) according to JIS K 6760 of 10.0 to 40.0 g / 10 min, with 10 to 35 parts by weight of low or medium density polyethylene resin of 0.935 g / cm ³ or less, which has a melt index according to JIS K 6760 of 0.2 to 2 g / 10 min, a percentage of molecules having a molecular weight of 500,000 or more of 10% by weight or more and a value of the critical shear rate of 0.5 s ^-1 or less, wherein the composition obtained by the melt blending has a value of has the critical shear rate of 10 s ^-1 or less.

The present invention also relates to a process for producing a resin-coated paper by melt blending 90 to 65 parts by weight of high-density polyethylene resin of 0.960 g / cm ³ or more, which has a melt index according to JIS K 6760 of 10.0 to 40 , 0 g / 10 min, with 10 to 35 parts by weight of low or medium density polyethylene resin of 0.935 g / cm ³ or less, which has a melt index according to JIS K 6760 of 0.2 to 2 g / 10 min, a percentage Molecules having a molecular weight of 500,000 or more of 10% by weight or more and having a critical shear rate value of 0.5 s ^-1 or less, and the resulting polyethylene type resin composition is melt-extruded coating a base paper therewith, said resin composition being obtainable by melt blending and having a critical shear rate value of 10 s ^-1 or less.

1 is a graph showing the relationship between (shear load and first normal load difference) and (shear speed): the ordinate refers to the shear load and the first normal load difference, the abscissa relates to the shear rate. In the figure, the curve denoted by a shows the relationship of the shear stress and the curve denoted by b the relationship of the first normal load difference.

The The present invention will now be explained in detail.

In In the present specification, the term "critical shear rate" means that value for the Shear rate at which shear load and first normal load difference have the same value, which at 240 ° C by the below-described Procedure with a rotational viscometer of the cone plate type determined are.

The high-density polyethylene resin used in the first resin layer in the resin-coated paper of the present invention has a melt flow index according to JIS K 6760 (hereinafter referred to as MFR) in the range of 10.0 to 40.0 g / 10 min, preferably 10.0 to 30, 0 g / 10 min, and a density of 0.960 g / cm ³ or more, preferably 0.962 g / cm ³ or more. In the present invention, the critical shear rate value of the high density polyethylene is preferably about 10 to 100 s ^-1 , more preferably about 20 to 80 s ^-1 . As the high density polyethylene resin (hereinafter referred to as HDPE) having the above-mentioned physical properties, as examples besides HDPE itself, there are mentioned copolymers obtained from ethylene as a main component and a lower α-olefin such as propylene or butene or mixtures thereof.

When the MFR of the HDPE is less than 10.0 g / 10 min, the adhesion strength between the base paper and the resin layer and the molding processability deteriorate. If the MFR is more than 40.0 g / 10 min, ease of miscibility of the resins, moldability and the like deteriorate. If the density is less than 0.960 g / cm ³ , the fabrication properties such as the cuttability deteriorate, so that no desirable Result can be obtained. HDPE products which are different in MFR, density, molecular weight and molecular weight distribution can be used singly or as a mixture thereof as long as the MFR and density of these resins are in the above ranges.

On the other hand, the low density polyethylene resin (hereinafter referred to as LDPE) or the medium density polyethylene resin (hereinafter referred to as MDPE) used in the resin layer has an MFR in the range of 0.2 to 2 g / 10 min, preferably less than 1.0 g / 10 min and not less than 0.2 g / 10 min, a density of 0.935 g / cm ³ or less, preferably 0.930 g / cm ³ or less, a percentage of molecules having a molecular weight of 500,000 or more of 10% by weight or more, preferably 12% by weight or more, and a critical shear rate value of 0.9 s ^-1 or less, preferably 0.4 s ^-1 or less.

If the MFR of the LDPE is less than 0.2 g / 10 min, the ease of miscibility of the resins, the adhesion strength between the base paper and the resin layer, moldability, etc. deteriorate. If the MFR is more than 2 g / 10 min Shaping processability deteriorates. If the density is more than 0.935 g / cm ³ , the adhesive force between the base paper and the resin layer, the moldability, etc. deteriorate, so that no desired result is obtainable. When the percentage of the resin of the molecules having a molecular weight of 500,000 or more is less than 10% by weight, the molding processability becomes insufficient and the sizing occurs. Therefore, this is not desirable. The molecular weight is determined by a GPC method performed by a Waters Co. apparatus 150-C (column: GMH-XL HT 8 mmφ × 30 cm × 3 columns, solvent: 1,2,4-trichlorobenzene, temperature: 135 ° C, flow rate: 1 ml / min).

The critical shear rate value of the LDPE or MDPE must be 0.5 s ^-1 or less. If the value for the critical shear rate is more than 0.5 s ^-1 , problems such as poor moldability, formation of a gel in the resin layer, etc. occur.

1 Fig. 12 is a diagram showing the relationship between (shear stress and first normal strain difference) and (shear velocity). In 1 the ordinate refers to the shear stress and the first normal stress difference, the abscissa relates to the shear velocity. In 1 For example, the curve labeled a indicates the shear stress relationship and the curve labeled b indicates the relationship of the first normal stress differential.

In the present invention, the value for the critical shear rate is determined using a cone-plate type of rotational viscometer (Rheometrics Mechanical Spectrometer: Diameter of cone plate 25 mm, angle 0.1 rad, temperature 240 ° C) and represents the shear rate at the point where the shear load and the first normal load difference in 1 become equal to each other (the intersection of the curve a with the curve b). Shear load and first normal load difference are calculated by the following equations: Shear Load = (viscosity) × (shear rate) First normal load difference = (coefficient of first normal load difference) × (shear rate) 2

In the resin layer of the resin-coated paper of the present invention, there is used a compound resin of a polyethylene type resin composition prepared by preliminarily adding 90 to 65 parts by weight of an HDPE having the above physical properties with 10 to 35 parts by weight of a LDPE or MDPE, which have the above-mentioned physical properties, melt-blended. The value of the critical shear rate of the compound resin must be 10 s ^-1 or less, more preferably 8 s ^-1 or less. If the value for the critical shear rate is more than 10 s ^-1 , there is an undesirable tendency for a gel to form. The composition obtained by the blending performed in the melt of the HDPE and the LDPE or MDPE has an MFR of preferably 1.4 to 36 g / 10 min, more preferably 4.0 to 15 g / 10 min, and a Density of preferably 0.932 to 0.970 g / cm ³ .

It is believed that in the present invention, gelation is suppressed due to the viscoelastic properties of the resin at the high resin temperature in melt extrusion coating. It is presumed that the properties of the resin change from viscous to elastic at the above-mentioned critical shear rate of 10 s ^-1 or less, so that the gelation is improved by reducing the likelihood of gelation, by grinding and kneading a (possibly. formed) gels, etc. is suppressed. As a method for melt blending the HDPE and the LDPE or MDPE in the above proportions, a simple melt blending method, a multi-stage melt blending method, etc. may be used. For example, a Banbury mixer, pressure kneader, hot roll kneader, extruder, twin screw extruder, etc. are used. The HDPE and the LDPE or MDPE are coated by extrusion with a melt-coating extruder in a dry-blended state without prior Blending in the melt, molded, the adhesion strength between the base paper and the resin layer, the ease of miscibility of the resins, the moldability, etc., deteriorate.

Various Additives such as UV absorbers, heat stabilizers, Antistatic agents, antioxidants, light stabilizers, lubricants, nucleating agents, dye etc. can be neatly cleaned in the resin composition used in the resin layer of the polyethylene type, as long as they do not have the effect of reduce the present invention. These additives can be prepared in advance the HDPE and LDPE or MDPE used or these Resins at the time of mixing in the melt or this Resins at the time of Schmelzextrusionsüberziehens, in the form of a so-called masterbatches by adding the additives in high Concentration to the resins is added.

When The base paper used in the present invention may include each one of a natural Mainly from pulp paper ordinary naturally Pulp, a mixed paper of natural pulp and synthetic Fiber and a synthetic paper of synthetic pulp, synthetic Fiber or synthetic resin film material are used. The Base paper may contain sizing agents, reinforcing agents, fillers, Fixative, pH adjuster, stain, fluorescent Whitening agents etc. included.

to Preparation of the resin-coated paper of the present invention a so-called melt extrusion coating method is used, where the coating carried out is made by the above-mentioned polyethylene-type resin composition in the form of a film on moving base paper through the slit die a melt extruder is poured. Usually, the melt extrusion temperature is preferably 280 to 340 ° C. It is preferable to use the base paper of an activating treatment such as a corona discharge treatment or a flame treatment before coating of the base paper with the polyethylene-type resin composition suspend. Although the thickness of the resin layer is not particularly limited, usually has the resin layer a coating thickness from about 5 to 50 microns on.

In addition, the inventors have carried out a purposeful research and as a result thereof It has been found that the present invention can be more effectively carried out successfully if the following condition is satisfied: in a resin-coated paper obtainable by coating each side of a base paper with a resin layer of a resin composition mainly of polyethylene resins Coating, the difference between the coating weight of the resins in the resin layer on the side on which an image-forming layer is to be formed, ie, the second resin layer, and the coating weight of the resins in the resin layer on the back side an image-forming layer is to be formed, ie, the first resin layer, 3 g / m ² or more. Also, it has been found that the present invention can be more effectively carried out when the first resin layer is made of a compound resin composition obtained by preliminarily forming a high density polyethylene resin and a low density polyethylene resin or a medium density polyethylene resin the melt is mixed and when the critical shear rate value of the compound resin is 10 s ^-1 or less. Furthermore, it has been found that the present invention can be more remarkably carried out when, as the low density polyethylene resin or the medium density polyethylene resin, a polyethylene resin having a melt flow rate of less than 1 g / 10 min and not less than 0.2 g / 10 min Compound resin represents.

When Low or medium density polyethylene resin for the first Resin layer can various polyethylene resins are used, e.g. High-pressure polyethylene resins low density (low density polyethylene resins, manufactured by an autoclave process or a process carried out in the pipe), linear low density polyethylene resins, medium density polyethylene resins Density, copolymers of ethylene and an α-olefin such as propylene or butylene, Carboxy-modified polyethylene resins and mixtures thereof.

Use ratio, density, MFR and the value for the critical shear rate of the polyethylene resin is lower or medium density and the high density polyethylene resin for the first Resin layer were from a synthesis point of view determined as the result of experiments carried out by a trial and error method looking at e.g. the lightness the miscibility of the resins, the molding processability as well as the preventive effect on the formation of a gelatinous Foreign matter in the production of a base for a picture-making material, the adhesion between Base paper and resin composition layer of the image forming material base as well as the performance characteristics of the base for an image-forming material, such as curling properties, cuttability, feeling in the hand and nerve were performed, whereby the present invention has been successfully completed is. In particular, amounts the amount of high density polyethylene resin incorporated into the resin composition from the high density polyethylene resin and the polyethylene resin lower or medium density, 90 to 65 parts by weight, preferably 85 to 70 parts by weight, more preferably 80 to 70 parts by weight. Is the amount of the resin used less than 65 parts by weight, worsen curling properties, cuttability, feeling in the hand, nerve and the like, the backing for the Image-educational material disadvantageously. Exceeds the amount of used Resin 90 parts by weight, the ease of miscibility worsened the resins, moldability, adhesion strength between the base paper and the resin layer, etc. disadvantageously.

The MFR of the high-density polyethylene resin for the first resin layer is 10 to 40 g / 10 min, preferably 10 to 30 g / 10 min. If the MFR of the resin is less than 10 g / 10 min, the adhesion strength between the base paper and the resin layer, the high-speed processing performance, etc. disadvantageously deteriorate. If the MFR of the resin is more than 40 g / 10 min, moldability, etc. are deteriorated, and also the corrugation properties tend to deteriorate. This is therefore not desirable. The density of the high-density polyethylene resin is 0.960 g / cm ³ or more. If the density is less than 0.960 g / cm ³ , the curling property, nerve, etc. are adversely affected. The density is preferably 0.962 g / cm ³ or more.

On the other hand, the MFR of the low- and medium-density polyethylene resin for the first resin layer is in the range of 0.2 to 2 g / 10 min. If the MFR is less than 0.2 g / 10 min, the ease of miscibility of the Resins, the adhesion strength between the base paper and the resin layer, the processability at high speed, etc. disadvantageously. When the MFR exceeds 2 g / 10 min, the moldability deteriorates and the curling property tends to be deteriorated. This is therefore not desirable. The MFR is preferably less than 1 g / 10 min and not less than 0.2 g / 10 min. The density of the low density polyethylene resin is 0.935 g / cm ³ or less. When the density exceeds 0.935 g / cm ³ , the moldability of the resin composition, the adhesion strength between the base paper and the resin layer, etc. disadvantageously deteriorate. The density is preferably 0.930 g / cm ³ or less. The percentage of molecules having a molecular weight of 500,000 or more in these resins is 10% by weight or more, preferably 12% by weight or more. In these resins, when the percentage of molecules having a molecular weight of 500,000 or more is less than 10% by weight, the molding processing properties are insufficient, particularly in terms of sizing. Therefore, this is not desirable.

As already described above, the first resin layer is preferably formed by using a compound resin, which by previous Melting in the melt is made. As a method of preparation of the compound resin by previously mixing the polyethylene resin low or medium density with the high density polyethylene resin in the melt can a simple melt mixing process, a multi-step melt blending process etc. are applied. Advantageously, e.g. a procedure applied, wherein predetermined amounts of the polyethylene resin lower or medium density with the high density polyethylene resin as well optionally various additives such as an antioxidant, lubricant and the like with an extruder, twin screw extruder, hot roll kneader, Banbury mixer, a pressure kneader or the like. In the melt and pelleting the resulting mixture. Are the resins from Polyethylene type to a coating formed by melt extrusion by placing them in one only simply mixed condition directly into a melt extruder, instead of using them in the form of a compound resin, deteriorate the liability strength between the base paper and the resin layer, the lightness of the Miscibility of the resins, the molding properties, etc. in disadvantageous Wise.

The value of the critical shear rate of the above-mentioned compound resin is suitably 10 s ^-1 or less, preferably 8 s ^-1 or less, particularly in order to prevent the formation of a gelatinous foreign matter occurring with time in extrusion melt coating. If the value for the critical shear rate exceeds 10 s ^-1 , gelatinous foreign matter is undesirably formed. It can be considered that the preventive effect brought about by the present invention is due to the formation of a gelatinous foreign matter due to the viscoelastic properties of the resin at the high resin temperature during melt extrusion coating. It is to be supposed that the properties of the resin change from viscous to elastic at the critical shear rate, so that the effect is brought about by reducing the likelihood of gelation, improving the grinding and kneading of a gel (if any).

As described above, preferably, that side of the base paper of the resin-coated paper of the present invention on which an image-forming layer is to be formed is coated with a resin composition of mainly one or more polyethylene-type resins. As the polyethylene type resins, various polyethylene type resins may be used, for example, low, medium, high density polyethylene resins, linear low density polyethylenes, copolymers of ethylene and an α-olefin such as propylene or butylene, carboxy-modified polyethylene resins and mixtures thereof , Polyethylene resins may be used which differ in density, MFR, molecular weight and molecular weight distribution, although usually polyethylene resins having a density in the range of 0.91 to 0.97 g / cm ³ , an MFR of 1 to 30 g / 10 min a molecular weight in the range of 20,000 to 250,000, alone or as a mixture thereof, are advantageously used.

The difference between the coating weight of the resin (s) in the second coating layer and the coating weight of the resins in the first coating layer is preferably 3 g / m ^2, more preferably 5 g / m ^2, most preferably 7 g / m ² . If the difference in the coating weight between the front and the back is less than 3 g / m ² , an image-forming material obtained by using the corresponding resin-coated paper as a base curls toward the back of its image-forming layer, causing the problem a very difficult handling of the image-forming material. In addition, undesirably, the cuttability of the support for the image-forming material or the image-forming material having the support for the image-forming material deteriorates. More specifically, the following problem is often caused: the support for the image-forming material or the image-forming material having the support for the image-forming material is cut to a desired size with a cutting machine such as a guillotine cutter or a precision printing cutter when cut, the support for the image-forming material can not be accurately cut, and whisker-like protrusions are formed on the sectional surface of the support for the image-forming material to impair its commercial value. In contrast, the under-body for the image-forming material according to the present invention or an image-forming material having this carrier for the image-forming material is allowed to have a fairly good cut surface.

As described above, the undercoat for an image-forming material is preferably prepared by a melt-extrusion coating process, wherein the coating is carried out by passing the polyethylene-type resin composition in the form of a film on moving base paper through the Slotted die of a melt extruder. In this case, the temperature of the molten film is preferably 280 to 340 ° C. As a slit template, flat matrices of a T-die, L-die and the shape of a fish-tail are preferable. The diameter of the slot opening is preferably 0.1 to 2 mm. It is preferable to subject the base paper to an activating treatment such as a corona discharge treatment or a flame treatment before coating the base paper with the resin composition. Also, it is preferable to blow an ozone-containing gas against the molten resin composition on the side on which the composition is brought into contact with the base paper, and then coat the running base paper with a resin layer as described in JP 61-42254 B. The base paper is preferably coated with the first and second resin layers by a so-called tandem extrusion coating method, wherein the resin layers are formed by extrusion coating one after another, preferably sequentially. If necessary, the base paper may be coated by a multi-layer extrusion coating method, imparting a multi-layered structure of two or more layers of each of the first or second resin layers. The surface of the second (front) resin layer of the image forming support base may be formed into a glossy surface, the fine rough surface described in JP 62-19732 B, a matte surface, a silky surface or the like. Usually, the first resin layer is preferably processed to a dull surface. The thickness of the second resin layer is preferably in the range of 9 to 100 μm, more preferably 12 to 55 μm. The thickness of the first resin layer is preferably in the range of 5 to 95 μm, more preferably 8 to 50 μm.

Various additives may be incorporated into the first and second resin layers of the image-forming support base. The following various additives may be used in suitable combination: for example, white pigments (eg, titanium oxide, zinc oxide, talc, and calcium carbonate), fatty acid amides (eg, stearamide and arachidamide), and metal salts of fatty acids (eg, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, and calcium palmitate ) described in JP 60-3430 B, JP 63-11655 B, JP 1-38291 B, and JP 1-38292 B and JP 1-105245 A, various antioxidants (eg, hindered phenols, hindered amines and phosphorus- and sulfur-containing Antioxidants), blue pigments and dyes (cobalt blue, ultramarine blue and phthalocyanine blue), magenta pigments and dyes (eg, cobalt violet, fast violet and manganese violet) described in JP 1-105245 A, and the fluorescent whitening agents and UV absorbers used in JP 2-254440 A are described. The additives are preferably incorporated in the form of a masterbatch or a compound of the resins. In particular, for incorporating the additives into the compound resin composition for the first resin layer used for carrying out the present invention, the additives may be preceded by the high density polyethylene resin and the low or medium density polyethylene resin or at the time of preparation of the compound resin or resin Resins in melt extrusion coating, in the form of a masterbatch prepared by adding the additives in high concentration to the resins.

As a base paper, natural pulp paper of mainly ordinary natural pulp (base paper of mainly natural pulp, hereinafter abbreviated as "base paper") is preferable. Mixed paper of natural pulp and synthetic fiber or so-called synthetic paper of synthetic pulp, synthetic fiber or synthetic resin film material may also be used. Although the thickness of the base paper is not particularly limited, its basis weight is preferably 40 to 250 g / m ² .

When Pulp, composed of the preferred base paper used is, advantageously, such a clean selected natural pulp as described in JP 58-37642 A, JP 60-67940 A, JP 60-69649 A and JP 61-35442 A is described. Being natural pulp will be beneficial Wood pulps such as softwood pulp, hardwood pulp and mixed pulp made of softwood hardwood, e.g. a usual one Bleaching treatment with chlorine, hypochlorite or chlorine dioxide, one Alkali extraction, alkali treatment and possibly an oxidation bleaching have been subjected to hydrogen peroxide. It can be different Pulps, such as kraft pulp, sulfite pulp, and soda pulp become.

Various additives may be incorporated into the base paper in the production of a stock slurry. It is advantageous, for example, to incorporate the following additives in a suitable combination: sizing agents such as metal salts of fatty acids and / or fatty acids, alkyl ketene dimer emulsions or epoxidized higher fatty acid amides which are described in JP 62-7534 B, alkenyl or alkyl succinate anhydride emulsions, rosin derivatives etc., dry reinforcing agents such as anionic, cationic or amphoteric polyacrylamides and polyvinyl alcohols, cationic starches, vegetable galactomannans, etc., wet reinforcing agents such as polyamine-polyamide-epichlorohydrin resins, etc., fillers such as clay, kaolin, calcium carbonate, titanium oxide, etc., fixing agents such as water-soluble aluminum salts (eg aluminum chloride and aluminum umsulfate), pH adjusting agents such as sodium hydroxide, sodium carbonate, sulfuric acid, etc., and color pigments, chakuryo dyes, fluorescent whitening agents and the like described in JP 63-204251 A and JP 1-266537 A.

Various water-soluble Polymers, antistatic agents and additives can be used in the base paper a spray or Schildklebpresse be introduced. It is advantageous that the following materials in suitable combination: water-soluble polymers such as starch-type polymers, Poly (vinyl alcohol) type polymers, gelatin type polymers, Polyacrylamide-type polymers and cellulose-type polymers, the in JP 1-266537 A, antistatic agents such as alkali metal salts (e.g., sodium chloride and potassium chloride), alkaline earth metal salts (e.g. Calcium chloride and barium chloride), colloidal metal oxides (e.g. colloidal silica), organic antistatic agents (e.g., polystyrenesulfonates) etc., emulsions and latices, such as emulsions and latexes of ethylene-vinyl acetate copolymers, Petroleum resin emulsions, etc., pigments such as clay, kaolin, talc, barium sulfate, Titanium oxide, etc., pH adjusting agents such as hydrochloric, phosphoric, citric, sodium hydroxide, etc., and the additives listed above as examples, such as color pigments, Dyes and fluorescent whitening agents.

The Base paper is preferably one that has a smooth surface a Bekk smoothness (according to JIS P 8119) of 100 seconds or more, more preferably 200 seconds or more, having. For making a base paper with a Bekk smoothness of 100 seconds or more usually, in a big one Proportion amount, hardwood pulp used, composed of short fiber is, and a smoothness easily yields, with the hardwood pulp beaten with a striker to reduce the amount of long fiber as much as possible. Especially it is preferred to beat the pulp so strongly that a fiber length and freedom of pulp after impact treatment with a 42-mesh residue from 20 to 45% or with 200 to 350 CSF. Then one will pulp slurry, contains the internal additives, made to paper to give a uniform formation, with a conventional one Paper machine such as a Fourdrinier paper machine, Zyliner paper machine or the like by such a suitable papermaking method as it is described in JP 58-37642 A, JP 61-260240 A and JP 1-284762 A. is. After papermaking, the paper is fed with a machine calender, Supercalender, hot calender or the like calendered. This way, a base paper with a Bekk smoothness of 100 seconds or more.

On the second resin layer may be coated by such a backcoat layer as described in JP 61-84643 A, JP 1-92740 A, JP 1-102551 A and JP 1-166035 A is described or exemplified, after the second resin layer has an activating treatment, such as a corona discharge treatment, Flame treatment or the like. Was subjected. To prevent one Electrification can be different Back coating layers be formed by placing them on the first resin layer of the resin-coated Paper of the present invention, after the first Resin layer of activating treatment such as corona discharge treatment, Flame treatment or the like. Was subjected. In the backcoat layer can in suitable combination inorganic antistatic agents, organic antistatic agents, hydrophilic binders, latices, hardeners, pigments, surfactants Means etc. may be incorporated, which e.g. JP 52-18020 B, JP 57-9059 B, JP 57-53940 B and JP 58-56859 B and JP 59-214849 A and JP 58-184144 A are described.

The support for the image-forming material can be used for various purposes by forming various photographic layers thereon by coating. For example, it can be used for producing color printing paper, monochrome printing paper, phototype printing paper, photocopying printing paper, reversal photographic material that is negative or positive for a silver salt diffusion transfer method, printing material, etc. For example, a silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsion layer can be formed. A multilayer silver halide photographic layer can be formed by incorporating color couplers into photographic silver halide emulsions. A photographic layer for a silver salt diffusion transfer process can be formed. As the bonding agent for the above photographic layers, in addition to ordinary gelatin, hydrophobic high molecular substances such as polyvinylpyrrolidones, polyvinyl alcohols, sulfate ester compounds of polysaccharides, etc. can be used. Various additives may be incorporated in the above-mentioned photographic layers. For example, the following additives may be incorporated in suitable combination: sensitizing dyes such as cyanine dyes, merocyanine dyes, etc., chemical sensitizers such as water-soluble gold compounds, sulfur compounds, etc., antifoggants or stabilizers such as hydroxytriazolopyrimidine compounds, mercapto-heterocycles, etc., curing agents such as formaldehyde. , Vinylsulfone, aziridine compounds, etc., coating aids such as alkylbenzenesulfonates, sulfosuccinic ester salts, etc., antifouling agents such as dialkylhydroquinone compounds, etc., fluorescent whitening agents, sharpness-improving dyes, Antistatic agents, pH adjusters, fogging agents, and water-soluble iridium and rhodium compounds, etc., which are incorporated in the preparation and dispersion of the silver halide.

The photographic materials according to the present invention Invention can such treatment methods (e.g., exposure, development, termination, Fixation, bleaching and stabilization), such as she by Goro Miyamoto in "Shashin Kankozairyo To Toriatsukaiho (Photosensitive Materials and Handling Methods), "Shashin Gijutsu Koza 2, KYORITSU-SHUPPAN Ltd., National Diet Library, 1981, Tokyo, Japan, are described. The multilayer color photographic silver halide material can with a development solution treated with a development accelerator such as benzyl alcohol, a thallium salt, phenidone or the like. It can also work with one development solution be treated, which contains substantially no benzyl alcohol.

The Support base for the Image-educational material may be as various vehicle documents for an image-educational material for heat transfer reproduction can be used by putting on it various image acquisition layers for heat transfer reproduction by coating formed. As synthetic resins used in the image-receiving layers for heat transfer reproduction Examples of resins used with ester bonds, such as Polyester, polyacrylic ester, polycarbonate, polyvinyl acetate, polyvinyl butyrate, Styrene acrylate, vinyl toluene acrylate resins, etc., resins with urethane bonds, such as polyurethane resins, etc., resins with amide bonds such as polyamide resins etc., resins with urea linkages such as urea resins, etc., polycaprolactam resins, resins Base styrene, polyvinyl chloride resins, vinyl chloride, vinyl acetate copolymer resins and polyacrylonitrile resins to call. Apart from these resins, mixtures or copolymers may also be used these resins and the like. Be used.

Next the above synthetic resins can Mold releasing agents, pigments and the like into the image receiving layers for heat transfer reproduction be introduced. The aforementioned mold releasing agents include e.g. solid waxes such as polyethylene waxes, amide waxes, Teflon powder, etc., fluorine-containing surfactants Or phosphate ester type agents and silicone oils. Of these mold release agents, the silicone oils are the most prefers. As silicone oils can be oil-like be used, although curable are preferred. As a hardenable silicone oils As examples, those of the type of reaction hardening, light curing and catalytic hardening to call. The silicone oils of the type of reaction hardening are particularly preferred. The silicone oils of the reaction curing type include amino-modified ones Silicone oils, Epoxy-modified silicone oils etc. one. The amount of added aforementioned reactive silicone oil is preferably 0.1 to 20% by weight, based on the weight of the image-receiving layer. As the aforementioned pigments are extender pigments such as silica, calcium carbonate, Titanium oxide, zinc oxide, etc. are preferred. The thickness of the image-receiving layer is preferably 0.5 to 20, more preferably 2 to 10 microns.

The support for the image-forming material may also be used as various support substrates for an ink-jet printing material by coating thereon various ink-receiving layers. Various binder materials may be incorporated in the ink receiving layers to improve the drying properties of the ink, the sharpness of the image, and so on. Specific examples of the binder materials are aqueous adhesives of various types of gelatin such as limestone, acid or enzyme-treated gelatin, gelatin derivatives and reaction products of gelatin with anhydride of dibasic acid (eg phthalic, maleic or fumaric acid), etc., ordinary polyvinyl alcohols differ in their degree of saponification, carboxy-modified, cation-modified and amphoteric polyvinyl alcohols and derivatives thereof, starches such as oxidized, cationized, etherified starches, etc., cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, etc., synthetic polymers such as polyvinylpyrrolidones, polyvinylpyridinium halides, Polysodium acrylates, acrylic acid-methacrylic acid copolymer salts, polyethylene glycols, polypropylene glycols, polyvinyl ethers, alkyl vinyl ether-maleic anhydride copolymers, styrene-maleic anhydride copolymers and salts thereof, polyethyleneimines, etc., conjugated diene copolymer latexes of styrene-butene adiene copolymers, methyl methacrylate-butadiene copolymers, etc., vinyl acetate-based polymer latexes of polyvinyl acetates, vinyl acetate-maleic acid ester copolymers, vinyl acetate-acrylic ester copolymers, ethylene-vinyl acetate copolymers, etc., latices of acrylic polymers or copolymers such as acrylic ester polymers, methacrylic ester polymers , Ethylene-acrylic ester copolymers, styrene-acrylic ester copolymers, etc., vinylidene chloride-based copolymer latexes or functional group-modified polymer latices obtainable from these various polymers using a functional group such as a carboxyl group-containing monomer, and thermosetting resins such as melamine resins , Urea resins, etc., adhesives based on synthetic resins of polymethyl methacrylates, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyrals, alkyd resins, etc., and inorganic binder materials such as alumina sols, silica sols, etc., which in JP 3-24906 B, JP 3-281383 A and JP 4-240725 A. The above binders can be used individually or in combination.

Besides the binders, various additives may be incorporated in the ink receiving layer or the ink jet printing material. For example, the following various additives may be incorporated in suitable combination: surfactants such as anionic surfactants (eg long chain alkylbenzenesulfonates and long chain and preferably branched alkylsulfosuccinic acid ester salts), nonionic surfactants (eg polyalkylene oxide ethers of long chain and preferably branched alkyl phenols and polyalkylene oxide ethers , long-chain alkylphenols) and fluorinated surfactants described in JP 47-9303 B, US 3,589,906 etc. are described; Silane coupling agents such as γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, etc .; Hardeners for polymers such as active halides, vinylsulfone, aziridine, epoxy, acryloyl, isocyanate compounds, etc .; Antiseptics such as p-hydroxybenzoic acid ester, benzisothiazolone, isothiazolone compounds, etc. described in JP 1-102551 A; Color pigments, dyes, fluorescent whitening agents and the like described in JP 63-204251 A and JP 1-266537 A; Anti-yellowing agents such as sodium hydroxymethanesulfonate, sodium p-toluenesulfinate, etc .; UV absorbers such as benzotriazole compounds having a hydroxydialkylphenyl group in the 2-position, etc .; Antioxidants such as the hindered polyphenol compounds described in JP 1-105245A; Pencil writing agents such as organic or inorganic fine particles having a particle size of 0.2 to 5 μm of starch particles, barium sulfate, silica, etc., and like the organopolysiloxanes described in JP 4-1337 B; and pH adjusting agents such as sodium hydroxide, sodium carbonate, sulfuric, hydrochloric, phosphoric, citric acid, etc .; octyl alcohol; and defoaming agents based on silicone.

Moreover The inventors have made purposeful investigations to one Extrusion melt coating process which is designed so that in the production of with a polyethylene-type resin-coated paper by extrusion fusion coating the applied process conditions, not productivity deteriorate a good molding processability of the resin layer and good adhesion between the resin layer and the base paper and gelation prevent in the resin layer. As a result, it was found that the above object can be solved in the following way: in the process for producing resin-coated paper by extrusion coating one side of a base paper with polyethylene-type resin the polyethylene-type resin from an extruder at a screw revolution speed extruder extruded in the melt, which is higher than the critical Rotation speed (Nc).

worin

Nc :

kritische Schraubenumdrehungsgeschwindigkeit (Upm)

CSR:

Wert für die kritische Schergeschwindigkeit des Harzes s^–1

H:

Schraubenkanaltiefe im Unterteil des Rumpfs (cm)

D:

Trommelöffnung (cm).

The aforesaid critical revolution speed (Nc) is calculated by the following method:

wherein

Nc:

critical screw revolution speed (rpm)

CSR:

Value for the critical shear rate of the resin s ^-1

H:

Screw channel depth in the lower part of the fuselage (cm)

D:

Drum opening (cm).

The Screw revolution speed of one in the present invention used extruder can easily with a commercial Rotation indicator to be measured, equipped with the extruder is.

is the screw revolution speed of the aforementioned extruder not higher as the critical speed of rotation, through the above Formula (1) is calculated to prevent gelation insufficient in the resin layer. This is therefore not desirable.

In practice, to extend the operating range in extrusion melt coating, the critical rotational speed is preferably low. When process measure Measures can be used to reduce the critical speed of rotation like a measure, in which a resin with such a low value for the critical shear rate as possible within the range specified in the present invention is used, singly or in combination of two or more appropriate measures be applied.

For extrusion coating base paper with a polyethylene-type resin described by Ma The base paper is melt-extruded with the resin either directly or after previously treating the surface of the base paper to be bonded with a conventional surface activation such as corona discharge treatment, flame treatment, anchor coating treatment or the like to improve the adhesion between the base paper and the polyethylene-type resin are extrusion-coated.

The Extrusion coating can be done using conventional Procedures and devices are performed. For example is it done by putting the polyethylene-type resin into a molten thin film through the die of an extruder at a resin temperature of 280 up to 340 ° C extruded, the molten thin Film leads to a pressure roller and that on the pressure roller guided Base paper without or after the above surface activation treatment with the molten thin Movie over the pressure roller and a cooling roller coated by extrusion.

Even though the thickness of the aforementioned polyethylene type resin layer is not particularly is restricted she usually lies in a thickness range of about 5 to 50 microns.

When the resin used as a polyethylene-type resin a high density polyethylene and a low density polyethylene or a medium density polyethylene.

to Production of the base paper, which in the present invention preferably is used conventional Paper machines such as a Fourdrinier paper machine, cylinder paper machine, etc. used become.

Further was the result of a research purposefully conducted by the inventors found out that the Object of the present invention in a particularly effective manner solved can be when a substrate has a film thickness nonuniformity index Rpy in the Papermaking direction (defined below) of 140 mV or less having.

Of the used in the present specification, "film thickness nonuniformity index Rpy "is as follows Are defined. That is, a film thickness gauge is used in which a sample between two spherical ones sensors is run, and the thickness deviation of the sample is in Form of electrical signals determined by an electronic micrometer. It will be in the sensitivity range of the electronic micrometer of ± 15 μm / ± 3V, after Zero setting, in the paper-forming direction at a constant speed scanned at 1.5 m / min to determine the thickness variation of the sample in the Determine paper production direction.

The measured signal values thus obtained are subjected to a fast Fourier transformation with an FFT analyzer using a sliding window as a time window. The current spectrum (unit: mV ² ) is determined on the basis of the arithmetic mean value of a 128-fold integration, and the current values in a frequency range of 2 to 25 Hz are summed. The sum is multiplied by 2/3 and the square root of the product is calculated. The value thus obtained is referred to as "film thickness nonuniformity index Rpy" (unit: mV).

Specifically, the film thickness nonuniformity index Rpy is determined in the following manner. A film thickness measuring instrument is used in which a sample is passed between two spherical probes of about 5 mm in diameter having a measuring pressure of about 30 g / bar, and the thickness deviation of the sample in the form of electrical signals by an electronic probe Micrometer measured. It is scanned in the sensitivity range of the electronic micrometer of ± 15 μm / ± 3V, after zero adjustment, in the paper-forming direction at a constant speed of 1.5 m / min to measure the thickness deviation of the sample in the paper-forming direction. The measured values thus obtained are subjected to a fast Fourier transform (FFT) with an FFT analyzer (input signal: AC ± 10 mV, sampling: 512 units) under the following treatment conditions: a sliding window is used as the time window, and the Frequency range is set to 50 Hz. The current spectrum (unit: (mV) ² ) on a linear scale is determined on the basis of the arithmetic mean value of a 128-fold integration, and the squares of the current values on a linear scale in a frequency range of 2 to 25 Hz are summed. The sum is multiplied by 2/3 and the square root of the product is calculated. In this way, the film thickness nonuniformity index Rpy can be determined. For further frequency analysis conditions, the analysis is performed under the initial conditions.

It has been found that the object of the present invention synergistically ge is dissolved by using a base paper having a film thickness nonuniformity index Rpy in the papermaking direction defined in the present specification of 140 mV or less and a resin composition mainly of a polyethylene type specific compound resin as a coating resin , In particular, the cuttability of a resin-coated paper-type support for an image-forming material is synergistically improved by the present invention, so that the image-forming material support base of the present invention or an image-forming support material has a very good sectional area exhibit. In addition, it has been found that the object of the present invention is clearly solved by the use of a base paper having a film thickness non-uniformity index Rpy defined in the present specification of 135 mV or less in the papermaking direction. Further, it has been found that the object of the present invention is also clearly solved by using, in the polyethylene type compound resin, a low- and medium-density polyethylene resin having a melt flow rate of less than 1 g / 10 min and not less than 0.2 g / 10 min. In this way, the present invention has been brought to its successful conclusion.

• (1) Als eingesetzte natürliche Pulpe wird Hartholz-Pulpe, die aus Kurzfaser zusammengesetzt ist und leicht eine gute Glätte ergibt, in einer großen Anteilsmenge herangezogen. Insbesondere wird z.B. die in JP 60-69649 A beschriebene Hartholz-Pulpe in einem Mengenanteil von 60 Gew.% oder mehr, vorzugsweise von 70 Gew.% oder mehr, eingesetzt.
• (2) Bezüglich der Bedingungen zum Schlagen der Pulpe, wurde die Pulpe mit einem Schlaggerät so geschlagen, daß ihr Gehalt an Langfaser so viel wie möglich herabgesetzt wurde.
• Insbesondere wird die Pulpe wie folgt geschlagen: die bezüglich der Länge gemittelte Faserlänge, gemessen gemäß Japan Tappi Paper Pulp Test Method Nr. 52-89 "Test Methods of Fiber Length of Paper and Pulp", werden auf 0,4 bis 0,75 mm, vorzugsweise auf 0,45 bis 0,7 mm, noch bevorzugter auf 0,45 bis 0,65 mm, der Gewichtsprozentsatz an Faser mit einer Faserlänge von 1 mm oder weniger bezüglich der kumulativen Verteilung auf 70% oder mehr und der Wert für die Freiheit auf 200 bis 330 CSF eingestellt.
• (3) Das Basispapier wird mit einer Fourdrinier-Papiermaschine so erzeugt, daß man eine einheitliche Formation erhält, indem man ein geeignetes Papiererzeugungsverfahren auf eine Stoffaufschlämmung anwendet, die innere Additive enthält. Insbesondere wird beispielsweise jedes der folgenden Verfahren angewandt. (i) Die Stoffaufschlämmung wird einer geeigneten Turbulenz ausgesetzt. (ii) Es wird eine Fourdrinier-Papiermaschine eingesetzt, die solch einen geeigneten oberen Entwässerungs-Mechanismus aufweist, wie er in JP 61-284762 A beschrieben ist. (iii) Es werden ein mehrstufiges Naß-Preßverfahren, vorzugsweise ein drei- oder höherstufiges Preßverfahren, als Preßverfahren in einem Naß-Teil durchgeführt, und es ist eine Glättungswalze in der letzten Stufe des Preßteils vorgesehen.
• (4) Es wird ein Massedichte-Pressen beim Trocknen von Naßgewebe angewandt. Insbesondere wird das Naßgewebe einem solchen mehrstufigen Massedichte-Preßverfahren unterzogen, wie es in JP 3-29945 A beschrieben ist.
• (5) Das Basispapier wird erzeugt und dann mit einer Kalandermaschine, einem Super-Kalander, Heiß-Kalander oder dgl. kalandert. Insbesondere ist es bevorzugt, z.B. das in JP 60-126397 A beschriebene Heiß-Kalanderverfahren durchzuführen.

The base paper of mainly natural paper used in the present invention has a film thickness nonuniformity index Rpy in the paper-forming direction as defined in the present specification (the term "film thickness nonuniformity index Rpy in the papermaking direction" is hereinafter abbreviated as "film thickness nonuniformity index Rpy ") of 140 mV or less, preferably 135 mV, more preferably 130 mV or less. The study conducted by the present inventors revealed that the base paper having a film thickness nonuniformity index Rpy of 140 mV or less is particularly obtainable by the following methods individually, preferably in combination of 2 or more thereof, more preferably 3 or more thereof, most preferably 4 or more thereof.

• (1) As the natural pulp used, hardwood pulp composed of short fiber and easily giving good smoothness is used in a large proportion. In particular, for example, the hardwood pulp described in JP 60-69649 A is used in a proportion of 60% by weight or more, preferably 70% by weight or more.
• (2) As for the conditions for beating the pulp, the pulp was beaten with a beater so as to reduce its content of long fiber as much as possible.
• Specifically, the pulp is beaten as follows: the length-averaged fiber length measured in accordance with Japan Tappi Paper Pulp Test Method No. 52-89 "Test Methods of Fiber Length of Paper and Pulp" is set to 0.4 to 0.75 mm , preferably at 0.45 to 0.7 mm, more preferably at 0.45 to 0.65 mm, the weight percentage of fiber having a fiber length of 1 mm or less in terms of cumulative distribution to 70% or more, and the value for Freedom set to 200 to 330 CSF.
• (3) The base paper is formed on a Fourdrinier paper machine so as to obtain a uniform formation by applying a suitable paper-making method to a stock slurry containing internal additives. In particular, for example, each of the following methods is used. (i) The stock slurry is exposed to suitable turbulence. (ii) A Fourdrinier paper machine having such a suitable upper dewatering mechanism as described in JP 61-284762A is used. (iii) A multi-stage wet pressing method, preferably a three-stage or higher-stage pressing method, is carried out as a pressing in a wet part, and a smoothing roll is provided in the last stage of the compact.
• (4) A mass density press is used in drying wet tissue. In particular, the wet tissue is subjected to such a multi-level mass density pressing method as described in JP 3-29945 A.
• (5) The base paper is produced and then calendered with a calendering machine, super calender, hot calender or the like. In particular, it is preferable to perform, for example, the hot calendering method described in JP 60-126397A.

When Pulp, from which the base paper is composed, becomes the one above described suitably selected natural pulp in an advantageous Although used, if necessary, synthetic pulp and synthetic fiber besides the natural pulp can. As natural Pulp will be wood pulp such as softwood pulp, hardwood pulp and mixed pulp of softwood / hardwood used, e.g. a usual one Bleaching treatment with chlorine, hypochlorite or chlorine dioxide of an alkali extraction, Alkali treatment and optionally a bleaching process by Oxidation with hydrogen peroxide, oxygen or the like as well as a Combination of these treatment methods have been subjected. It can be different Pulp like a kraft pulp, Sulfite pulp, soda pulp, etc. are used.

As already described above, a composition consisting of various water-soluble Polymer or hydrophilic colloids or latices, an antistatic agent and other additives, in or on the base paper with a sizing press or a sizing press or by coating such as with a blade coating method, air knife coating method or the like. On or applied. It is advantageous to incorporate the following materials in suitable combination: water-soluble polymers or hydrophilic colloids such as starch-type polymers, polyvinyl alcohol-type polymers, gelatin-type polymers, polyacrylamide-type polymers and cellulose-type polymers in JP 1-266537 A; Emulsions and latexes such as petroleum resin latices, emulsions or latexes of copolymers obtainable by using at least ethylene and acrylic acid (or methacrylic acid) as components described in JP 55-4027 A and JP 1-180538 A, and emulsions and latices of Styrene-butadiene, styrene-acrylic, vinyl acetate-acrylic, ethylene-vinyl acetate, butadiene-methyl methacrylate copolymers and carboxy-modified copolymers obtainable therefrom; Antistatics such as alkali metal salts (eg, sodium chloride and potassium chloride), alkaline earth metal salts (eg, calcium chloride and barium chloride), colloidal metal oxides (eg, colloidal silka), organic antistats (eg, polystyrene sulfonates), etc .; Pigments such as clay, kaolin, calcium carbonate, talc, barium sulfate, titanium oxide, etc .; pH adjusting agents such as hydrochloric, phosphoric, citric, sodium hydroxide, etc .; and the additives exemplified above such as color pigments, dyes and fluorescent whitening agents.

Although the thickness of the base paper is not particularly limited, its basis weight is preferably 20 to 200 g / m ² .

The side of the base paper of the image-forming support base sheet according to the present invention on which an image-forming layer is to be formed is preferably coated with a resin having film-forming properties. As the resin having film-forming properties, thermoplastic resins such as polyolefin, polycarbonate, polyester, polyamide resins, etc. are preferable. Among these, for reasons of ease of the melt extrusion coating process, the polyolefin resins are more preferable, and polyethylene type resins are particularly preferable. As the polyethylene type resins, various polyethylene type resins may be used, for example, low density polyethylene resins, medium density polyethylene resins, high density polyethylene resins, linear low density polyethylenes, copolymers of ethylene and an α-olefin such as propylene or butylene, carboxy-modified Polyethylene resins and mixtures thereof. Polyethylene-type resins differing in their density, MFR, molecular weight and molecular weight distribution can be used although it is usually used advantageously, polyethylene resins, individually or as a mixture thereof, having a density in the range of 0.91 to 0.97 g / cm ³ , an MFR of 1 to 30 g / 10 min and a molecular weight in the range of 20,000 to 250,000. The above-mentioned side can be coated with the electron beam-curable resin described in JP 60-17104B.

On the surface of the second resin layer of the resin-coated paper of the present invention, by coating, such a back coat layer as described in JP 61-84643 A, JP 1-92740 A, JP 1-102551 A and JP 1-166035 A can be formed after the second resin layer has been subjected to an activating treatment such as a corona discharge treatment, flame treatment or the like. In order to prevent electrification, various back coat layers may be formed by application to the first resin layer after the first resin layer has been subjected to an activating treatment such as corona discharge treatment, flame treatment or the like. In the backcoat layer, inorganic antistats, organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants, etc. may be incorporated in a suitable combination, which are described in, for example, JP 52-18020 B, JP 57-9059 B, JP 57-53940 B and JP 8-56859 B and JP 59-214849 A and JP 58-184144 A are described.

When a result of a complete investigation carried out by the inventors It was found that the Object of the present invention in a particularly effective manner solved in the following way in the process of producing resin-coated paper by extrusion coating one side of a base paper with polyethylene-type resin the polyethylene type resin from an extruder at a resin pressure extruded at the screw end of the extruder in the melt, which higher than the value for the critical resin pressure (Pc) is.

Pc:

kritischer Harzdruck am Ende der Schraube (kgf/cm²)

n:

Viskosität des Harzes bei 240°C bei einer Schergeschwindigkeit von (πND)/(60H) (N ist Schraubenumdrehungsgeschwindigkeit)

CSR:

kritische Schergeschwindigkeit des Harzes (s^–1)

H:

Schraubenkanaltiefe im unteren Teil des Rumpfs (cm)

n:

Steigung der Schraube

D:

Trommelöffnung (cm)

θ:

Steigungswinkel der Schraube (Grad).

The value for the aforementioned critical resin pressure (Pc) is calculated by the following method: Pc = (Z × η × CSR) / (9.8 × 10 5 × H) (2) where Z is the extension length of the screw: Z = π × n × D / cos θ wherein

pc:

critical resin pressure at the end of the screw (kgf / cm ² )

n:

Viscosity of the resin at 240 ° C at a shear rate of (πND) / (60H) (N is screw revolution speed)

CSR:

critical shear rate of the resin (s ^-1 )

H:

Screw channel depth in the lower part of the fuselage (cm)

n:

Slope of the screw

D:

Drum opening (cm)

θ:

Lead angle of the screw (degrees).

Of the screw end resin pressure used in the present invention of the extruder (the resin pressure in front of a breaker plate) may be light with a commercial Resin pressure measuring device determined which the extruder is equipped with. In the present case becomes a state where the resin pressure without turning the screw in the filled with the resin Extruder is constant, referred to as a state in which the Resin pressure is zero.

is the above-mentioned resin pressure at the screw end of the extruder is not higher than the value calculated by the above equation (2) for the critical Resin print, drops the prevention of gelation in the resin layer insufficient. This is therefore not desirable.

When process measure to increase the resin pressure can as an example a measure using a resin that is so low in JIS K 6760 defined melt flow rate (hereinafter referred to as MFR only) as possible within the having a range specified in the present invention, a measure when you open it the die lip decreases, a measure in which the opening area of a Crushing plate reduced in the extruder, a measure in which you sieve packs in the flow channel for the Resin used in the extruder, a measure in which the number the sieve packs increased, as well as a measure in which one sieve packs of the fine mesh area starts. These measures can used individually or in combination of two or more thereof become.

In In practice, for extending the operating range in the extrusion-melt coating method, the Value for the critical resin pressure preferably low. As a measure to Reduction of the value for the Critical resin pressure as an example is a measure of making a resin that low values for viscosity or critical shear rate as possible within the range specified in the present invention and a measure to call at which the length the screw is reduced. These measures can be used individually or in combination be applied by two or more.

Further will, in some cases, a gel is formed to cause a problem when the extruder at a reduced rotational speed due to, for example a cleaning measure the die lip or at a transition change of the inserted Harz is operated. In this case, gelation can be prevented be made by the resin pressure to a higher pressure than that of the Execution of the set the present invention to be observed critical resin pressure.

To the Extrusion coating a base paper with the through the die of the aforementioned extruder in The melt-extruded polyethylene-type resin may be the base paper with the resin either directly or after a conventional one Surface activation treatment the surface to be joined of the base paper such as a corona discharge treatment, flame treatment, Anchor coat treatment or the like to improve the adhesion strength between the base paper and the polyethylene-type resin by extrusion become.

The extrusion coating process may be carried out using conventional methods and apparatus. For example, it is carried out by extruding the polyethylene-type resin into a molten thin film through the die of the extruder at a resin temperature of 280 to 340 ° C, passing the molten thin film on a pressure roll and placing it on the die Pressure roll guided base paper without or after the above surface activation treatment with the molten thin film on the pressure roller and a chill roll by extrusion coating.

Even though the thickness of the aforementioned polyethylene type resin layer is not particularly is restricted she usually lies in a thickness range of about 5 to 50 microns.

When that for The polyethylene-type resin used in the resin layer becomes high density polyethylene as well Low or medium density polyethylene used.

It is to assume that the according to the present Invention enabled suppression a gel formation due to the viscoelastic properties of the Resin at high resin temperature in the melt extrusion coating process is conditional. It can be assumed that the suppression by the reduction in the likelihood of gelation, by the Occurrence of a grinding and kneading of an optionally yourself forming gel, etc., with the causes being brought about, by setting the resin pressure at the end of the screw to a higher value for the Pressure as the value for sets the critical resin pressure.

Moreover was discovered as a result of a research purposefully carried out by the inventors, that the Object of the present invention in a particularly effective manner solved when the center-plane average roughness SRa of the first resin layer in the longitudinal direction (machine direction) at a cut value of 0.8 mm, using a three-dimensional probe-type surface roughness meter is determined, has a value in the range of 0.6 to 2.0 microns.

The term "center-plane sectional roughness SRa used in the present invention at a cut value of 0.8 mm, which is obtained by means of a three-dimensional probe-type surface roughness meter," is defined by the following equation:

In In the above equation, Wx is the length in the X-axis direction (paper-forming direction) of a Sample surface area, Wy the length in the Y-axis direction (direction, perpendicular to the paper-forming direction) of the sample surface area and sa the area of the sample surface area.

Specifically, the center-plane average roughness SRa can be obtained with a meter and an analyzer as a three-dimensional probe-type surface roughness meter or a three-dimensional roughness analyzer under the following conditions: cut value: 0.8 mm, Wx = 20 mm , Wy = 8 mm, ie Sa = 160 mm ² . For data processing in the X direction, 500 units are sampled and scanned in the X axis direction in 17 lines or more.

It It was found that the Object of the present invention is achieved in a synergistic manner, by putting the first resin layer of the resin-coated paper so make yours Center-plane average roughness SRa to a value in the range from 0.6 to 2.0 μm is set, wherein a resin composition of mainly one specific polyethylene-type compound resin as a resin for the first Resin layer used. In particular, chill roll stains that occur at the production of the vehicle underlay resin-coated paper type for producing an image-forming material can result, by the particular features and measures of the present invention suppressed in a synergistic way, So that the Support base for a Image-forming material according to the present Invention or a carrier pad exhibiting image-forming material does not result in quality problems caused by the transfer of chill roll spots could be caused. In addition, it was found out; that the task of the present Invention is solved in a particularly remarkable way by the surface of the Resin layer on the back so made that the center-plane average roughness defined in the present specification SRa is set to a value in the range of 0.8 to 1.6 μm. Further became found out that the Object of the present invention is particularly pronounced solved by a polyethylene resin is lower in the polyethylene-type compound resin or medium density, which is a melt flow rate of less than 1 g / 10 min and not less than 0.2 g / 10 min.

As described above, the first resin layer of the resin-coated paper is preferable is made to have a center-plane average roughness SRa in the range of 0.6 to 2.0 μm. When the value for the center-plane average roughness SRa is less than 0.6 μm, sufficient prevention of the formation of chill roll spots becomes difficult. Moreover, when the support for the image-forming material or an image-forming material having the support base is wound up in the form of a roll after production, the front and back sides tend to stick together, namely, the blocking tends to occur. This is therefore not desirable. On the other hand, if the center-plane average roughness SRa has a value of more than 2.0 μm, the prevention of the formation of chill roll spots becomes insufficient. Further, when the support for an image-forming material or an image-forming material having the support base is wound up in the form of a roll, the respective surfaces tend to be feathered. This is therefore also undesirable. The center-plane average roughness SRa of the surface of the back resin layer of the support sheet for an image-forming material according to the present invention is preferably 0.8 to 1.6 μm. For making the surface of the first resin layer correspondingly to set its center-plane average roughness SRa to a value in the range of 0.6 to 2.0 μm, it is sufficient to use a cooling roll having a surface roughness capable of forming an SRa Value in the above range. As for a concrete method of manufacturing a corresponding cooling roll, the cooling roll may be made by, for example, Bossier method, etching method, dry sand blasting method, liquid honing method, etc. described in JP 60-6944 A and JP 62-150247 A. The liquid honing method is preferable. It is also preferable that prior to an appropriate use of the chill roll, the resin-coated paper is preliminarily produced by using the chill roll, and the center-plane average roughness SRa of the back surface of the resin-coated paper is measured and confirmed.

As already described above can be a composition consisting of different water-soluble polymers or hydrophilic colloids or latices, an antistatic agent and of additives, in or on the base paper with a Sizing press or a sizing press or by coating like with a blade, air knife coating method or the like. On or applied.

Advantageous is to introduce the following materials in suitable combination: water-soluble polymers or hydrophilic colloids such as starch-type polymers, polyvinyl alcohol-type polymers, Gelatin type polymers, polyacrylamide type polymers and polymers of the cellulose type described in JP 1-266537 A; emulsions and latices, such as petroleum resin latices, emulsions or latices of Copolymers, available by using at least ethylene and acrylic acid (or Methacrylic acid) as Ingredients described in JP 1-180538 A and emulsions and latexes of styrene-butadiene, styrene-acrylic, vinyl acetate-acrylic, Ethylene-vinyl acetate, butadiene-methyl methacrylate copolymers and of from these available Carboxy-modified copolymers; Antistatic agents such as alkali metal salts (e.g., sodium chloride and potassium chloride), alkaline earth metal salts (e.g. Calcium chloride and barium chloride), colloidal metal oxides (e.g. colloidal silica), organic antistatic agents (e.g., polystyrenesulfonates) etc.; Pigments such as clay, kaolin, calcium carbonate, talc, barium sulfate, Titanium oxide, etc .; pH adjusting like phosphoric citric acid, Sodium hydroxide, etc .; and the additives listed above as examples such as color pigments, dyes and fluorescent whitening agents.

As a base paper, base paper is preferably used which has a smooth surface with a Bekk smoothness (according to JIS P 8119) of 100 seconds or more, more preferably 200 seconds or more. For producing base paper having a Bekk smoothness of 100 seconds or more, hardwood pulp composed of short fiber and easy to provide smoothness is usually used in a large proportion, thus whipping the hardwood pulp with a percussion device, that it is reduced as much as possible in terms of the proportion of longer fiber. In particular, it is preferable to beat the pulp so that the fiber length and the value of the pulp freedom after hitting a value of the 42-mesh residue are from 20 to 45% and a value for the freedom from 200 to 350, respectively CSF are set. Then, a stock slurry containing internal additives is made into paper to obtain a uniform formation with a conventional paper machine such as a Fourdrinier paper machine, a cylinder paper machine or the like by such a suitable paper making method as disclosed in, for example, JP 58-37642 A, JP 61-260240 A and JP 61-284762 A is described. After papermaking, the paper is calendered with a calendering machine, super calender, hot calender or the like. In this way, the base paper having a Bekk smoothness of 100 seconds or more on the production scale can be produced. Although the thickness of the base paper used for carrying out the present invention is not particularly limited, its basis weight is preferably 20 to 250 g / m ² .

The The present invention will now be described more concretely with reference to FIGS Examples explained however, it is within the scope of the present invention not limited to the examples.

example 1

70 parts by weight of an HDPE having an MFR of 15.0 g / 10 min, a density of 0.967 g / cm ³ and a critical shear rate value of 60 s ^-1 (A in the following Table 1) and 30 wt. Parts of an LDPE having an MFR of 0.6 g / 10 min, a density of 0.924 g / cm ³ , a percentage of molecules having a molecular weight of 500,000 of 15 wt% or more and a value for the critical shear rate of 0 , 06 s ^-1 (e in Table 1) were previously melt-blended and then blended on paper having a high smoothness value and a basis weight of 170 g / m ² to a thickness of 25 μm from an extruder at a resin temperature of 320 ° C to coat the paper extruded, whereby the production was accomplished.

Regarding the A procedure for evaluating the molding processability in the melt extrusion coating process With the resins, the degree of settling was estimated by the corresponding length measured in the transverse direction of a resin-coated portion, and it has become the molding processability in terms of synthetic aspects rated, including the degree of formation of bars in a molten resin film, the occurrence of film break, depending on the degree of peel force, instability in the flow behavior because of effervescence or Ziehresonanz and the like.

The Grading is as follows: O: good, Δ: slightly inferior, but acceptable in practice, X: inferior and unacceptable in practice.

Regarding the Procedure for assessing the degree of liability between the base paper and Resin layer of the resin-coated paper, a sample was in her Base paper layer and resin layer decomposed by peeling, and it became the Area percentage the proportion of the base paper layer attached to the peeled resin layer adhered, which determines the adhesion strength between the base paper and the resin layer was evaluated. The gradation is as follows: O: good (area percentage: 100%), Δ: slightly inferior Adhesive strength, but acceptable in practice (area percentage: less than 100 and not less than 80%), X: low adhesion and unacceptable in practice (area percentage: less than 80%).

The procedure for estimating a gel formed in melt extrusion of the resins was as follows: after extruding the resins into a film over a period of 8 hours under the conditions of a predetermined temperature of 320 ° C and an extrusion rate of 2.5 kg / hr For example, pieces of the gel of 0.1 mm or more in 0.01 m ^{2 of} the film were counted and their numbers compared with the initial number, thereby estimating the gelation. The gradation is as follows: ○: the number of pieces of the gel after 8 hours was the same as the starting number, ×: the number of pieces of the gel after 8 hours was larger than the initial number.

Regarding the A procedure for evaluating the fabrication properties of the resin-coated paper, became the fabrication properties in terms of synthetic considerations rated, including the cuttability, starting from the degree of fluffing on the cut surface of a Sample formed by cutting the sample with a commercial one Guillotine cutter, including the abrasion resistance, from the degree of scratches on the surface of the resin layer that were induced, by putting the resin layer surfaces from two bows of the resin-coated paper and they rubbed against each other, including the Nerve of resin-coated paper and the like. The gradation is like follows: O: good, Δ: slight inferior, but acceptable in practice, X: inferior and not acceptable in practice.

In of Table 1 are physical properties of the HDPE and LDPE, which were used in the present example, and in the table 2, the evaluation results are given for the resin-coated Paper were obtained by the above evaluation procedures.

Examples 2 to 9

Resin-coated papers were obtained in the same manner as in Example 1, except that that instead of the combination of the HDPE and LDPE used in Example 1, the different resin compositions from the combination of HDPE and LDPE indicated in Table 1 were used in each case. Table 2 shows the evaluation results obtained for the resin-coated papers having the above evaluation procedures.

Examples 10 to 18

In Examples 10 to 17 were resin-coated Paiere in the same Manner as in Example 1, except that instead the combination of HDPE and LDPE used in Example 1, respectively the various resin compositions shown in Table 3 from a combination of the HDPE and LDPE were used. In table 3, the evaluation results are also given for the respective resin-coated papers with the above evaluation procedures were obtained.

In Example 18 was a resin-coated paper in the same manner obtained as in Example 1, except that a composition of HDPE and LDPE of the same species in the same proportions as in Example 1, but after mixing in the dry without mixing in the melt, was used. Table 3 also shows the corresponding ones Evaluation results indicated for the resin-coated paper according to the above Evaluation procedures were obtained.

Each of the resin-coated papers obtained in Examples 1 to 9 was immersed in a commercial aqueous hypochlorous acid solution for three days to be decomposed into the resin layer and the base paper. The separated resin layer was washed with water and air dried, whereupon the MFR, density and critical shear rate were determined according to the methods described above. Accordingly, it was found that, for the resin layers of all the resin-coated papers, the values for the MFR were 1.0 to 40 g / 10 min, for the density 0.930 to 0.971 g / cm ^3, and for the critical shear rate 20 s ^-1 or less.

Table 1

Table 2

Table 3

From the results shown in Table 2, it can be seen that the resin-coated papers are coated with a resin layer of a composition consisting of a mixture of 90 to 65 parts by weight of HDPE and 10 to 35 parts by weight of LDPE (the HDPE and LDPE in the present Invention specified physika and having a value for the critical shear rate of 10 s ^-1 or less (Examples 1 to 9) are qualitatively excellent in that they have good molding processability as well as adhesion strength and contain only a small amount of gel ,

On the other hand, the results shown in Table 3 indicate the following: if the conditions set forth in the present invention are not satisfied, for example, if the content of HDPE is more than 90 parts by weight (Examples 10 and 11), the moldability and the moldability are Adhesion strength does not look good, and it contains a large amount of gel. When the content of HDPE is less than 65 parts by weight (Example 12), the secondary molding processability is inferior. When the value of the critical shear rate of LDPE is more than 0.5 s ^-1 (Examples 13 to 16), a large amount of gel is contained. When the percentage of molecules having a molecular weight of 500,000 or more is less than 10% by weight (Examples 14 to 17), moldability is inferior.

In addition, if the value of the critical shear rate of the resin composition of HDPE with LDPE is more than 10.0 s ^-1 (Examples 10, 11 and 13 to 16), a large amount of gel is contained. When the composition of HDPE is merely dry-blended with LDPE as it is without being melt-blended (Example 18), the molding processability is inferior, so that no desired result is obtainable.

According to the present The invention will be a resin-coated polyethylene-type paper which provides good moldability of its resin layer has, with respect the liability strength between the resin layer and the base paper and only contains a small amount of gel.

Example 19

Mixed pulp of bleached sulfite hardwood pulp and bleached kraft-hardwood pulp in the ratio of 1: 1 was beaten to set its Canadian Standard Freeness value to 320 ml. Then, to 100 parts by weight of the pulp, 3 parts by weight of cationized starch, 0.2 part by weight of anionized polyacrylamide, 0.4 part by weight of an alkyl ketene dimer emulsion (based on ketene dimer) and 0.4 part by weight of polyamine-polyamide Epichlorohydrin resin and made paper having a basis weight of 160 g / m ² therefrom. The wet tissue thus obtained was dried at 110 ° C, then with an impregnating solution of 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of fluorescent whitening agent, 0.002 parts by weight of blue dye, 4 parts by weight of sodium chloride, 0.2 Parts by weight of citric acid and 93 parts by weight of water, in an amount of 25 g / m ² , dried in hot air at 110 ° C and then supercalendered at a linear pressure of 90 kg / cm to prepare base paper for a photographic support , The Bekk smoothness of the base paper in this case was 200 seconds.

When next became that side (the back) of the base paper, the backward too lay on the side on which an image-forming layer by coating is to be formed, subjected to a corona discharge treatment and then each having the polyethylene resin composition listed in Table 4 the resin coating weight shown in Table 4 at a resin temperature of 320 ° C and a running speed of the base paper of 150 m / min Melt extrusion coated, to form a first resin layer.

Subsequently, the front surface of the base paper was subjected to a corona discharge treatment and then coated with a resin composition of 20 parts by weight titanium dioxide pigment masterbatch of 47.5 wt% low density polyethylene resin (density 0.920 g / cm ³ , MFR = 8.5 g / 10 minutes), of 50% by weight hydrated alumina (0.75% by weight as Al ₂ O ₃ , based on the weight of titanium dioxide) of surface-treated anatase titanium dioxide pigment and 2.5% by weight zinc stearate of 65 parts by weight of low density polyethylene resin (density 0.920 g / cm ³ , MFR = 4.5 g / 10 min) and 15 parts by weight of high density polyethylene resin (density 0.970 g / cm ³ , MFR = 7.0 g / 10 minutes) each coated with the resin coating weight shown in Table 4 at a resin temperature of 320 ° C and a running speed of the base paper of 150 m / min by melt extrusion to form a second resin layer. The melt extrusion coating processes with polyethylene resin on the front and back were carried out as a so-called tandem process, wherein the extrusion coating processes were carried out one by one. In the present case, the surface of the titanium dioxide pigment-containing second resin layer of the resin-coated paper was made into a glossy surface and the surface of the first resin layer was made into a matte surface such as a paper surface.

Then, the surface of the first resin layer of the resin-coated paper of a corona Ent and then coated with the following back coat liquid. The backcoat liquid of colloidal silica and a styrene-based copolymer latex in the ratio of 1: 1 on a dry basis, which further contained a corresponding amount of 0.021 g / m ² sodium polystyrenesulfonate and suitable amounts of a coating aid and the like, was in a Amount of 0.21 g / m ² , based on the latex (weighed as solids), to obtain a base for an image-forming material.

Regarding the Procedures for Evaluating Shaping Processing Properties the polyethylene resin compositions for the first and second resin layers, respectively in the production of the carrier sheet carried out in the manner described above for a Image-forming material, to evaluate the extent the formation of a gelatinous Foreign matter and the performance characteristics of a sample obtained as a support for a picture-making material, the reviews were by now described procedures.

Regarding the Procedure for Evaluating the Formability of Polyethylene Resin Composition for the first resin layer in the production of the support for the image-forming material, The degree of sinking was estimated by the appropriate Length in Transverse direction of a coated with resin on the back portion determined was, and it was re the synthetic aspects of moldability, including the Level of coverage of strokes in a molten resin film, the Occurrence of film break, depending of the strength the pulling down, occurring instabilities in the flow behavior because of effervescence or Ziehresonanz and the like. Valued. The gradation is as follows: O: good, Δ: slight inferior, but acceptable in practice, X: inferior and not acceptable in practice.

The procedure for estimating the gelatinous foreign matter formed in the melt extrusion of the polyethylene resin composition for the first resin layer was as follows: after the composition was made into a film for 8 hours under conditions of a predetermined temperature of 320 ° C and an extrusion speed of 2.5 kg / h was extruded, the pieces of gelatinous foreign matter of 0.1 mm or more in 0.01 m ^{2 of} the film were counted and their number compared with the initial number, whereby the degree of formation of gelatinous foreign matter was estimated. The gradation is as follows: the number of formed pieces of the gelatinous foreign matter after 8 hours was the same as the initial number: Δ: the number of formed pieces of the gelatinous foreign matter after 8 hours is slightly higher than the initial number but acceptable in practice. x: the number of formed pieces of the gelatinous foreign matter after 8 hours was much larger than the initial number and unacceptable in the field.

Regarding the Procedure for assessing the degree of liability between the base paper and Support base for the Image-forming material each sample was placed in a thermo-hygrostat at 50 ° C and 60% RH for 24 h and then into the base paper layer and the Resin layer of the sample disassembled by peeling, and it became the Area percentage the proportion of the base paper layer attached to the peeled resin layer adhered, which determines the adhesion strength between the base paper and the first resin layer was evaluated. The gradation is the the following: O: good (area percentage: 100), Δ: slight inferior liability, but acceptable in practice (area percentage: less than 100 and not less than 80%), X: inferior adhesion strength and not acceptable in practice (area percentage: less than 80%).

Regarding the procedure for evaluating the curling properties of the support for the image-forming material, the evaluation was made as follows. First, after a corona discharge treatment, the surface of the titania pigment-containing second resin layer of the image-forming support base was made green with a blue-sensitive emulsion layer containing a yellow coupler having an intermediate layer containing a color mixing inhibitor sensitive emulsion layer containing a magenta coupler having a UV absorbing layer containing a UV absorber, a red-sensitive emulsion layer containing a cyan coupler, and a protective layer, whereby a color printing paper containing gelatin in one Total amount of 8 g / m ² , was generated. Each color-sensitive emulsion layer contained silver chlorobromide in an amount corresponding to 0.6 g / m ² silver nitrate and further gelatin sufficient for the preparation, dispersion and film formation of silver halide, suitable amounts of an antifoggant, sensitizing dyes, a coating aid, a curing agent and a thickening agent. an appropriate amount of a filter dye and the like. Subsequently, the produced color printing paper was stored at 35 ° C and ordinary humidity for 5 days and then developed under color development, whereupon the curl condition of the resulting color print measuring 8.2 cm × 11 , 7 cm, was estimated. The gradation is as follows: o sufficiently good corrugation properties, namely a slight minus corrugation (corrugation towards the Back coat layer) or flat, Δ: acceptable in practice, however, curl occurred to some extent, x: unacceptable in practice, namely severe undulation.

Regarding the Procedure for evaluating the cuttability of the carrier pad for the Image-forming material was the aforementioned color printing paper a length in the longitudinal direction of 11.7 cm cut with a precision pressure cutter, and the condition of the cut surface was evaluated. The gradation is as follows: O: good cuttability, namely almost no whisker-like formation Protrusions, Δ: acceptable in practice, however, formation of a small number whiskerartiger projections x: inferior cuttability and unacceptable in practice, namely Formation of a big one Number of whisker-like projections.

Regarding the Procedure for evaluating the smoothness of the support for the image-forming material, became the surface the above-mentioned color printing paper observed under light, the at an angle above it poured, and the visible gloss level was visually evaluated to become one To get judgment. The gradation is as follows: O: good smoothness of Support base, i.e. high visible gloss level, Δ: slightly inferior smoothness of Support base, i.e. slight reduced visible gloss, but acceptable in practice, x: inferior smoothness the backing, i.e. low visible gloss level and unacceptable in the Practice.

Tabelle 4 (Fortsetzung)

• (Anmerkung 1) bis (Anmerkung 3) in Tabelle 1 sind die folgenden:
• (Anmerkung 1) HDPE: ein Polyethylenharz hoher Dichte mit einer Dichte von 0,967 g/cm³ und einer MFR von 15 g/10 min.
• (Anmerkung 2) LDPE: ein Polyethylenharz niedriger Dichte mit einer Dichte von 0,924 g/cm³, einer MFR von 0,6 g/10 min, einem Prozentsatz an Molekülen mit einem Molekulargewicht von 500000 oder mehr von 15 Gew.% und einem Wert für die kritische Schergeschwindigkeit von 0,06 s^–1.
• (Anmerkung 3) Herstellverfahren des Polyethylenharz-Zusammensetzung-Kompound: das HDPE und das LDPE wurden in der Form von Pellets eines Kompound-Harzes eingesetzt, das durch vorherige, mit einem Knetextruder durchgeführte Vermischung in der Schmelze hergestellt war. Einfache Vermischung: das HDPE und das LDPE wurden eingesetzt, indem man sie in einen Schmelzextruder in der Form einer durch bloße Vermengung erhaltenen Mischung einspeiste.

The results obtained are shown in Table 4. Table 4

Table 4 (continued)

• (Note 1) to (Note 3) in Table 1 are the following:
• (Note 1) HDPE: a high-density polyethylene resin having a density of 0.967 g / cm ³ and an MFR of 15 g / 10 min.
• (Note 2) LDPE: a low density polyethylene resin having a density of 0.924 g / cm ³ , an MFR of 0.6 g / 10 min, a percentage of molecules having a molecular weight of 500,000 or more of 15 wt%, and a value for the critical shear rate of 0.06 s ^-1 .
• (Note 3) Preparation Method of Polyethylene Resin Composition Compound: The HDPE and LDPE were used in the form of pellets of a compound resin prepared by melt-mixing previously performed with a kneading extruder. Simple mixing: the HDPE and LDPE were used by feeding them into a melt extruder in the form of a blend obtained by mere blending.

From the results shown in Table 4, it can be clearly seen that the support sheets for an image-forming material (Samples Nos. 2, 3, 4, 5, 6, and 11) in which the difference in the resin coating weight is between two The first and second resin layers are 3 g / m ² or more, and the polyethylene resin in the back resin layer is a compound resin obtained by previously melt blending 90 to 65 parts by weight of high density polyethylene resin and 10 to 35 parts by weight of low-density polyethylene resin according to the present invention, are excellent base materials for an image-forming material, which have good moldability of the polyethylene resin composition, contain no formed gelatinous foreign matter, and the adhesion strength between base paper and resin layer, the corrugation properties, Cuttability and smoothness deliver satisfyingly good results. In particular, it is well understood that, for the synthetic performance characteristics of the image-forming support base, the difference in the resin coating weight between the first and second resin layers and the content of HDPE are preferably more than 3 g / m ² and 85-70 parts by weight, respectively.

On the other hand, when the content of the high-density polyethylene resin is more than 90 parts by weight (Sample No. 1), the moldability of the polyethylene resin composition is inferior, a large amount of gelatinous foreign matter is formed, and the adhesion strength between the base paper and the resin layer is not good. Therefore, this is not desirable. When the content of the high-density polyethylene resin is less than 65 parts by weight (Sample No. 12), the curling properties are not sufficiently good. Therefore, this is also not desirable. When mere blending is employed as a method for producing the polyethylene resin composition (No. 10), moldability and cuttability of the polyethylene resin are not good, and a large amount of gelatinous foreign matter is formed from an early start. Therefore, this is not desirable. In addition, if the difference in the resin coating weight between the first and second resin layers is less than 3 g / m ² (Sample Nos. 7, 8 and 9), cuttability and smoothness are not good. This is therefore not desirable.

Example 20

It became an experiment in the same way as in the case of No. 5 in Example 19 performed, with the exception that instead the polyethylene resin composition for coating shown in No. 5 in Example 19 the back each compound resin compositions used in the same way as in the case of No. 5 in Example 19, with the exception that the in Table 5 indicated polyethylene resins in the specified in Table 6 proportions were used. The results obtained are shown in Table 6.

Table 5

Table 6

From the results given in Table 6, it can be clearly seen that the underlays for an image-forming material according to the present invention (Sample Nos. 13 to 23) in which the polyethylene resin was used in the first resin layer is a compound resin composition obtained by previously melt-blending 90 to 65 parts by weight of high-density polyethylene resin having an MFR of 10 to 40 g / 10 min and a density of 0.960 g / cm ³ or more with 10 to 35 parts by weight of low density polyethylene resin having an MFR of 0.2 to 2 g / 10 min and a density of 0.935 g / cm ³ or less, a percentage of molecules having a molecular weight of 500,000 or more of 10 wt% or more and a value for the critical shear rate of 0.5 s ^-1 or less, wherein the value of the critical shear rate of the composition is 10 s ^-1 or less, are excellent support materials for an image-forming material, which has good properties the molding processability of the polyethylene resin composition, no gelatinous foreign matter formed, and the adhesion strength between the base paper and the resin layer , Curling properties and cuttability and smoothness provide pretty good results.

In particular, it will be readily apparent that to prevent the formation of a gelatinous debris, the low density polyethylene resin is preferably one that has an MFR of less than 1 g / 10 min. (See Sample Nos. 14 and 20 with Sample No. 21). The following is also readily apparent: in view of curling properties, the high-density polyethylene resin used in the present invention is preferably one having a density of 0.962 g / cm ³ or more (See Sample Nos. 14 and 18 with sample No. 19), and in view of the moldability, the preventive effect on the formation of a gelatinous foreign matter and the adhesion strength between base paper and resin layer, the high-density polyethylene resin is preferably one having an MFR in the range of 10 to 30 g / 10 min (See Sample Nos. 14, 18 and 22 with Sample No. 23). In addition, it will be readily apparent that the compound resin composition used in the practice of the present invention is preferably one that has a critical shear rate value of less than 8 s ^-1 (See Samples Nos. 13 to 20 and 22 to Samples Nos 21 and 23).

On the other hand, if the MFR of the low-density polyethylene resin is more than 2 g / 10 min (sample No. 26), the results on moldability and the degree of formation of a gelatinous foreign matter are insufficient. Therefore, this is not desirable. When the percentage of molecules having a molecular weight of 500,000 or more is less than 10% by weight (Sample Nos. 12 to 28), the moldability is disadvantageously inferior and there is a tendency to form a large amount of gelatinous foreign matter. When the MFR of the high-density polyethylene resin is more than 40 g / 10 min (Sample No. 30), the results in moldability, degree of gelatinous foreign matter formation, and adhesion strength between base paper and resin layer are insufficient. Therefore, this is not desirable. When the critical shear rate value of the compound resin composition is more than 10 s ^-1 (Sample Nos. 24 to 27 and 30), a large amount of gelatinous foreign matter is undesirably formed.

By The present invention makes it possible to obtain an excellent Support base resin-coated paper type for an image-forming material which does not produce any formed gelatinous debris in the resin layer on the back side to the page contains on the one picture education layer should be formed, which respect adhesion strength between resin layer and base paper gives good results, pretty much good properties with the corrugation properties, with cuttability and smoothness and can be produced quickly and stably.

Example 21

70 parts by weight of high density polyethylene with a MFR of 15.0 g / 10 minutes and a density of 0.967 g / cm ³ and 30 parts by weight of low density polyethylene with an MFR of 0.6 s ^-1 and a density of 0.924 g / cm ³ , a percentage of molecules having a molecular weight of 500,000 or more of 15% by weight and a critical shear rate of 0.06 s ^-1 were preliminarily melt-blended and then blended on paper having a high smoothness value and a basis weight of 170 g / m ^{2 was} extruded to a thickness of 25 microns from an extruder at a resin temperature of 320 ° C for coating the paper, whereby the corresponding product was prepared.

Regarding the procedure for evaluating the moldability in melt extrusion coating of the resins, the amount of sagging was estimated by determining the corresponding length in the transverse direction of a resin-coated portion, and the synthetic aspects of molding processability, including the extent of the formation of lines in one molten resin film, with regard to the occurrence of film breakage, depending on the severity of the drawdown, with regard to flowability instabilities due to ebulliance or drawdown, and the like. The gradation is as follows: O: good, Δ: slightly inferior but acceptable in practice, X: inferior and not acceptable in practice.

Regarding the Procedure for assessing the degree of liability between the base paper and the resin layer of the polyethylene type resin coated Papiers, was a sample in their base paper layer and polyethylene layer by peeling decomposed, and it became the area percentage the portion of the base paper layer is determined on the peeled polyethylene layer Adhesion strength between base paper and Resin layer was evaluated. The gradation is as follows: O: good (Area percentage: 100%), Δ: slight inferior liability, but acceptable in practice (area percentage: less than 100 and not less than 80%), X: inferior adhesion strength and not acceptable in practice (area percentage: less than 80%).

The procedure for estimating the gel formed upon melt extrusion of the resin was as follows. After the resins were extruded into a film for 8 hours under conditions of a predetermined temperature of 320 ° C and an extrusion rate of 2.5 kg / hr 0.1 mm in 0.1 m ^{2 of} the film was counted and its number compared to the initial number, thereby estimating gelation. The gradation is as follows: ○: the number of formed pieces of the gel after 8 hours was the same as the initial number, ×: the number of formed pieces of the gel after 8 hours was larger than the initial number.

Regarding the Procedure for evaluating the fabrication properties of the the resin of polyethylene-type coated Papiers were re the synthetic aspects evaluate the factory characteristics, including cuttability, based on the degree of fluffing on the cut surface of a made by cutting with a commercial guillotine cutter Sample, the abrasion resistance, based on the extent of Scratches on the surface of the resin layer formed by exposing the resin layer surfaces of 2 bows of the resin-coated paper and they rubbed together, including the Nerve of the resin-coated paper and the like. The gradation is as follows: O: good, Δ: slight inferior, but acceptable in practice, X: inferior and not acceptable in practice.

Examples 22 to 31

It An experiment was carried out in the same manner as in Example 21, with the exception that the species the resins for the polyethylene resin composition as shown in Table 7 amended were.

The The results obtained are shown in Tables 8 and 9.

Table 7

Table 8

Table 9

Out the results shown in Table 8 is clearly seen that with a polyethylene-type resin Papers produced by passing under melt extrusion conditions the coating process performs, wherein the screw revolution speed is higher than the critical revolution speed (Examples 22 to 27) excellent coated with a polyethylene type resin Present papers that contain no gel formed and good Results in moldability and adhesion between resin layer and Deliver base paper.

On the other hand the MFR of the high density polyethylene is less than 10 g / 10 min (Example 28), the processing characteristics are undesirable Way inferior. Is the screw revolution speed of the extruder below the critical rotational speed (Examples 29 to 31), gelation is undesirable Way serious. is the content of the high-density polyethylene more than 90 parts by weight (Example 31), the results fall in gel formation, adhesion between Base paper and resin layer and formability insufficient. Therefore, this is not desirable.

By the present invention makes it possible to obtain an excellent, to provide paper coated with a polyethylene grade resin, the good results in the moldability of its resin layer as well the liability strength between resin layer and base paper supplies and the formation of a Gels in the resin layer is able to prevent.

Example 32

Mixed pulp of 50% by weight of bleached kraft hardwood pulp, 35% by weight bleached sulfite hardwood pulp and 15% by weight bleached sulfite softwood pulp was beaten to adjust its fiber length to any value shown in Table 10 , Then, to 100 parts by weight of the pulp, 3 parts by weight of cationized starch, 0.2 part by weight of anionized polyacrylamide, 0.4 part by weight of alkylketene dimer emulsion (based on ketene dimer), 0.4 part by weight of polyamide-epichlorohydrin were used. Resin and appropriate amounts of a fluorescent whitening agent, a blue dye and a red dye to prepare a stock slurry. Thereafter, the stock slurry was placed on a Fourdrinier paper machine operating at a speed of 200 m / min and made into a fabric having a suitable size The fabric was subjected to a 3-stage wet pressing process at a linear pressure controlled in the range of 15 to 100 kg / cm in the wet part, treated with a smoothing roll, a 2-stage mass-density pressing at a subsequent wet Dry part in the range of 30 to 70 kg / cm controlled linear pressure and then dried. In the course of drying, the fabric thus obtained was subjected to a sizing press coating process comprising a size press coating liquid comprising 4 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 part by weight of fluorescent whitening agent, 0.002 part by weight of blue dye, 4 parts by weight of sodium chloride and 92 parts by weight Water, resulting in an amount of 25 g / m ² , dried so that the water content of the finally obtained base paper was set to 8 wt% in the bone dry state, and finally machine calendering under the condition shown in Table 10, and then subjected to a hot-soft calender treatment under the conditions of a temperature of 150 ° C and a linear pressure of 150 kg / cm. Thus, base paper was obtained for a base for an image-forming material having a basis weight of 170 g / m ² and the film thickness non-uniformity index Rpy shown in Table 10.

When next became that side (the back) of the base paper, the back to that side was on which by coating a picture education layer is subjected to a corona discharge treatment and then with each of the following polyethylene resin compositions according to the table 10 specified combination to a resin thickness of 26 microns at Resin temperature of 320 ° C and a running speed of the base paper of 150 m / min Melt extrusion coated.

When Polyethylene resin composition for coating the base paper was the following resin composition (1BL) according to the present invention or any of the following resin compositions used for comparison (2BL to 4BL).

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 were in the form of pellets of a polyethylene resin composition of a compound resin having a value for the critical shear rate of 4.4 s ^-1 , which was prepared by previously mixing the above resins in the melt with a kneading and extruding machine used.

Harzzusammenstzung (2BL): 80 parts by weight of high density polyethylene (1HD) and 20 parts by weight Low density polyethylene resin (11d), which are described in Table 11 were each used in the form of pellets by the Pellets of the resins in a merely mixed state in one Melt extruders were fed.

Resin Composition (3BL): 80 parts by weight of high density polyethylene resin (4HD) and 20 parts by weight of low density polyethylene resin (41d), which are described in Table 11, were in the form of pellets of a polyethylene resin composition of a compound resin a value for the critical shear rate of 17 s ^-1 , which was prepared by previously mixing the above resins in the melt with a kneading and extruding machine used.

Resin Composition (4BL): 50 parts by weight of high density polyethylene resin (1HD) and 50 parts by weight of low density polyethylene (11d), which are described in Table 11, were in the form of pellets of a polyethylene resin composition of a compound resin having a value for the critical shear rate of 1.0 s ^-1 , which was prepared by previously mixing the above resins in the melt with a melt extruder.

Subsequently, the front surface of a base paper was subjected to a corona discharge treatment and then coated with a resin composition of 20 parts by weight of a titanium dioxide pigment masterbatch of 47.5 wt% low density polyethylene resin (density 0.920 g / cm ³ , MFR = 8.5 g / 10 min) of 50% by weight hydrated aluminum oxide (0.75% by weight as Al ₂ O ₃ , based on the weight of titanium dioxide) surface-treated anatase titanium dioxide pigment and 2.5% by weight zinc stearate and 65 parts by weight of low density polyethylene resin (density 0.920 g / cm ³ , MFR = 4.5 g / 10 min) and 15 parts by weight of high density polyethylene resin (density 0.970 g / cm ³ , MFR = 7.0 g / 10 min) to a resin thickness of 32 microns at a resin temperature of 320 ° C and a running speed of the base paper of 150 m / min by melt extrusion coated. The melt extrusion coating methods with polyethylene resin on the front side and the back side were carried out by a so-called tandem method, wherein the extrusion coating methods were carried out one by one. In the present case, the surface of the second titanium dioxide pigment-containing resin layer of the resin-coated paper was made into a glossy surface and the surface of the first resin layer was processed into a matte surface such as a paper surface.

Then, the surface of the first resin layer of the resin-coated paper was subjected to a corona discharge treatment and then machine-coated with the following back-coating liquid. The colloidal silica back-coat liquid and a styrene-based copolymer latex in the ratio of 1: 1 on a dry basis, which further contained a corresponding amount of 0.021 g / m ² sodium polystyrenesulfonate and suitable amounts of a coating aid and the like, was used in an amount of 0 , 21 g / m ² , based on the latex (weighed as solids), to obtain a support for an image-forming material.

Regarding the Procedures for evaluating the molding processability of the Polyethylene resin composition for the first resin layer and the degree of gelatinous foreign matter in the first resin layer in the manner described above conducted Production method of the carrier pad for a Image-educational material as well as for the evaluation of the performance characteristics a sample obtained as a support for a Image-educational material, the reviews were with the now described Procedures performed.

Regarding the Procedure for evaluating the molding processability of the Polyethylene resin composition for the first resin layer in the production of the support for an image-forming material, The degree of sinking was estimated by looking at the corresponding Length in Transverse direction of a resin-coated portion on the back determined, and it was re synthetic aspects evaluated the molding processability, including the degree of formation of streaks in a molten resin film, the occurrence of film breakage, depending on the severity of the drawdown, one instability in the flow behavior because of effervescence or Ziehresonnanz and the like .. The gradation is as follows: O: good, Δ: slight inferior, but acceptable in practice, X: inferior and not acceptable in practice.

The procedure for estimating a gelatinous foreign matter formed in the melt extrusion of the polyethylene resin composition for the first resin layer was as follows: after the composition was made into a film for 8 hours under conditions of a predetermined temperature of 320 ° C and an extrusion rate of 2.5 kg / hr extruded, the pieces of the formed gelatinous foreign matter of 0.1 mm or more in 0.01 m ^{2 of} the film were counted and their number compared with the initial number, whereby the degree of formation of gelatinous foreign matter was estimated. The gradation is as follows: ○: number of formed pieces of the gelatinous foreign matter after 8 hours was the same as the initial number, Δ: the number of formed pieces of the gelatinous foreign matter after 8 hours is slightly higher than the initial number but acceptable in the Practice; x: the number of formed pieces of the gelatinous foreign matter after 8 hours was much larger than the initial number and unacceptable in the field.

Regarding the Procedure for evaluating the cuttability of the carrier pad for a Image-forming material, was the aforementioned color printing paper a length in the longitudinal direction of 11.7 cm cut with a precision pressure cutter, and the condition of the cut surface was evaluated. The gradation is as follows: ⊙: very good cuttability, namely almost no formation of whisker-like projections, ❍: good cutting ability, despite the formation of a small number of whisker-like projections; Δ: acceptable in practice, despite the formation of a somewhat larger number of whisker-like ones projections x: inferior cuttability and unacceptable in practice, namely Formation of a big one Number of whisker-like projections.

Regarding the procedure for evaluating the curling properties of the support for the image-forming material, the evaluation was made as follows. First, after a corona discharge treatment, the surface of the titania pigment-containing second resin layer of the image-forming support base was made green with a blue-sensitive emulsion layer containing a yellow coupler having an intermediate layer containing a color mixing inhibitor sensitive emulsion layer containing a magenta coupler having a UV absorbing layer containing a UV absorber, a red-sensitive emulsion layer containing a cyan coupler, and a protective layer, whereby a color printing paper containing gelatin in one Total amount of 8 g / m ² , was generated. Each color-sensitive emulsion layer contained silver chlorobromide in an amount corresponding to 0.6 g / m ² silver nitrate and further gelatin sufficient for the preparation, dispersion and film formation of silver halide, suitable amounts of an antifoggant, sensitizing dyes, a coating aid, a curing agent and a thickening agent. an appropriate amount of a filter dye and the like. Subsequently, the produced color printing paper was stored at 35 ° C and ordinary humidity for 5 days and then developed under color development, whereupon the curl condition of the resulting color print measuring 8.2 cm × 11 , 7 cm, was estimated. The gradation is like O: good enough corrugation properties, namely a slight minus corrugation (corrugation towards the recoating layer) or flat, Δ: acceptable in practice, but corrugation occurred to some extent, x: unacceptable in practice; Curl up.

Regarding the Procedure for assessing the degree of liability between the base paper and first resin layer of the backing for a Image-educational material, each sample was added in a thermo-hygrostat 50 ° C and Stored 60% RH for 24 hours and then by peeling in the base paper layer and the resin layer is decomposed, and it becomes the area percentage of the portion determined on base paper layer, the at the peeled resin layer Sticking, causing the adhesion between the base paper and the back Resin layer was evaluated. The grading is as follows: O good (area percentage: 100%), Δ: inferior liability, but acceptable in practice (areal percentage: less than 100% and not less than 80%), x: inferior adhesion strength and not acceptable in practice (area percentage: less than 80%).

Tabelle 11

• (Anmerkung 1) und (Anmerkung 2) in Tabelle 10 sind wie folgt:
• (Anmerkung 1): Es ist die bezüglich der Länge gemittelte
• Durchschnittsfaserlänge (mm) angegeben, gemessen für geschlagene Pulpe gemäß JAPAN TAPPI Paper Pulp Test Method No. 52-89 "Test Methods of Fiber Length of Paper and Pulp".
• (Anmerkung 2): Es ist der Filmdicke-Nichteinheitlichkeitsindex Rpy (mV) angegeben, gemessen mit dem in der vorliegenden Beschreibung spezifizierten Verfahren.

The results obtained are shown in Table 10. Table 10

Table 11

• (Note 1) and (Note 2) in Table 10 are as follows:
• (Note 1): It is the length-averaged one
• Average fiber length (mm), measured for beaten pulp according to JAPAN TAPPI Paper Pulp Test Method no. 52-89 "Test Methods of Fiber Lengths of Paper and Pulp".
• (Note 2): The film thickness nonuniformity index Rpy (mV) is given as measured by the method specified in the present specification.

Out The results given in Table 10 clearly show that the support documents for the picture-making material (Sample Nos. 1, 2, 5, 9, 12, 15, 18, and 22) obtained by use a paper with a film thickness nonuniformity index Rpy of 140 mV or less than a substrate and by coating the base paper on the back side to the side on which an image-forming layer is formed should, with a resin layer of a specific compound resin, prepared by previously performed in the melt mixing of the polyethylene resin high and low density according to the present Invention, excellent support documents for a Picture-making material, which has good properties moldability of the resin composition, not formed gelatinous Foreign matter contained, a much improved and pretty good Cuttability and quite good results in the corrugation properties and the liability between the base paper and the resin layer. Especially It is obvious that with respect to Cuttability of the backing for a Image-forming material The base paper is preferably one which a film thickness nonuniformity index Rpy of 135 mV or less, more preferably 130 mV or less, having.

On the other hand, if the film thickness nonuniformity index Rpy is more than 140 mV (Sample No. 23), the cuttability of the support for the image-forming material is undesirably inferior. When a compound resin resin composition (3BL) having a critical shear rate value of more than 10 s ^{-1 is used} as a resin composition for coating the back surface of the base paper (Sample Nos. 3, 7, 10, 13, 16 and 20) , a large amount of gelatinous foreign matter is formed disadvantageously. When a resin composition of a compound resin (4BL) having a high density polyethylene resin content of less than 65% by weight is used (Sample Nos. 4, 8, 11, 14, 17, and 21), the corrugation properties are not sufficiently good , This is therefore not desirable. When only simple mixing is used as a method for preparing the resin composition (Sample No. 5), moldability and cuttability of the resin composition are not good, and a large amount of gelatinous foreign matter is formed from an early start. Therefore, this is not desirable.

Example 33

It was an experiment in the same manner as in the case of sample No. 5 carried out in Example 32, with the exception that instead the polyethylene resin composition pellets used in No. 5 in Example 32 for coating the back Pellets of each polyethylene resin composition of a compound resin with the critical shear rate value given in Table 12 which was prepared by first preparing a polyethylene resin high density (1HD, given in Table 11) and a polyethylene resin low density (11d, given in Table 11) respectively in the in Table 12 indicated amounts by means of a kneading and Extrudiermaschine mixed in the melt.

The results obtained are shown in Table 12.

Table 12

From the results shown in Table 12, it can be clearly seen that the support sheets for an image-forming material according to the present invention (Sample Nos. 25 to 29) obtained by coating of the base paper comprising a resin composition of a compound resin having a critical shear rate value of 10 s ^-1 or less, obtained by pre-melt blending 90 to 65 parts by weight of high density polyethylene resin of 10 to 35 parts by weight Low-density polyethylene resin, are excellent support materials for an image-forming material which have good moldability properties of the resin composition, contain no formed gelatinous foreign matter, give a good property pattern in cuttability of the image-forming material support base, and give rather good results provide the adhesion strength between the base paper and the first resin layer. In particular, it is well understood that the content of the high-density polyethylene resin in the compound resin is preferably in the range of 85 to 70 parts by weight in view of the synthetic performance of the support for the image-forming material and more preferably in the range of 80 to 70 wt. Parts in view of a good property image in the cuttability of the support for the image-forming material is.

On the other hand the content of the high-density polyethylene resin is more than 90 parts by weight (No. 24), falls the molding processability of the polyethylene resin composition Inferior, forms a large amount of gelatinous foreign matter and the characteristics of the cuttability of the backing for the Image-building material as well as in the adhesion strength between basis paper and first resin layer is not satisfactory. This is not the case he wishes. is the content of the high-density polyethylene resin is less than 65 parts by weight (No. 30), the corrugation properties are not satisfactory out. Therefore, this is not desirable.

Example 34

It was an experiment in the same manner as in the case of sample No. 5 carried out in Example 32, with the exception that instead the pellets of the polyethylene resin composition used in No. 5 in Example 32 for coating the back Pellets of each polyethylene resin composition of a compound resin were used, which in the same manner as in the case of sample No. 5 in Example 32, with the exception that the in Table 11 described polyethylene resins in the specified in Table 13 proportions were mixed.

The results obtained are shown in Table 13.

Table 13

From the results shown in Table 13, it is well understood that the support sheets for an image-forming material according to the present invention (Sample Nos. 31 to 41) in which the polyethylene resin composition for the first resin layer is a compound resin composite resin by pre-melt blending from 90 to 65 parts by weight of high density polyethylene resin having a MFR of 10 to 40 g / 10 minutes and a density of 0.960 g / cm ³ or more with 10 to 35 parts by weight of low density polyethylene resin That is, an MFR of 0.2 to 2 g / 10 min, a density of 0.935 g / cm ³ or less, a percentage of molecules having a molecular weight of 500,000 or more of 10 wt% or more, and a value of has the critical shear rate of 0.5 s ^-1 or less, wherein the value of the critical shear rate of the compound resin is 10 s ^-1 or less, excellent support represent image-forming material properties which have good moldability properties of the polyethylene resin composition, do not contain a formed gelatinous foreign matter, give a good property pattern on cuttability of the image-forming material support base, and sufficiently good results in curl properties and adhesion strength between base paper and the first Provide resin layer.

In particular, it is well understood that to prevent the formation of a gelatinous debris, the low density polyethylene resin for the compound resin is preferably one having an MFR of less than 1 g / 10 min. (See Samples Nos. 32 and 38 with sample No. 39). The following is also obvious: in view of the corrugation properties, the high-density polyethylene resin for the compound resin is preferably one having a density of 0.962 g / cm ³ or more (see the sample Nos. 32 and 36 with sample no 37), and in view of the moldability of the polyethylene resin composition, the preventive effect on the formation of a gelatinous foreign matter, and the adhesion strength between base paper and first resin layer, the high density polyethylene resin is preferably one having an MFR in the range of 10 to 30 g / 10 minutes (See Sample Nos. 32 and 36 with Sample Nos. 40 and 41). In addition, it will be appreciated that the compound resin is preferably one which has a value for the critical shear rate of less than 8 s ^-1 (See samples Nos. 31-38 and 40 with samples Nos. 39 and 41).

On the other hand, when the MFR of the low-density polyethylene resin for the compound resin is more than 2 g / 10 min (Sample No. 44), the property pattern of moldability of the polyethylene resin composition and the degree of gelatinous foreign matter formation are not satisfactory. This is therefore not desirable. When the percentage of molecules having a molecular weight of 500,000 or more of the low density polyethylene resin for the composite resin is less than 10% by weight (Sample Nos. 43 to 46), the molding processability of the polyethylene resin composition is undesirably inferior and there is a large amount Tendency for a large amount of gelatinous foreign matter to be formed. When the MFR of the high-density polyethylene resin for the compound resin is more than 40 g / 10 min (Sample No. 48), molding processability of the polyethylene type resin composition, gelatinous foreign matter-forming degree, and adhesion strength between base paper and resin layer are insufficient. Therefore, this is not desirable. When the critical shear rate value of the compound resin composition is more than 10 s ^-1 (Sample Nos. 42 to 45 and 48), a large amount of gelatinous foreign matter is disadvantageously formed.

By The present invention makes it possible to obtain an excellent Support base of the resin-coated type Papers for to provide an image-forming material that is not formed gelatinous Foreign matter in the resin layer on the back to the side on the an image-forming layer is to be formed contains, remarkably has good cuttability, quite good results in corrugation properties and the liability delivers between the base paper and the resin layer and quickly and can be stably produced.

Example 35

70 parts by weight of high density polyethylene with a MFR of 15.0 g / 10 min and a density of 0.967 g / cm ³ and 30 parts by weight of low density polyethylene with a MFR of 0.6 g / 10 min, a density of 0.924 g / cm ³ , a percentage of molecules having a molecular weight of 500,000 or more of 15% by weight and a value for the critical shear rate of 0.06 s ^-1 were mixed in advance in the melt and then on paper with a high Smoothness value and a basis weight of 170 g / m ² extruded to a thickness of 25 microns from an extruder at a resin temperature of 320 ° C for coating the paper, whereby the production was accomplished.

Regarding the procedure for evaluating the molding processability in the melt-extrusion coating method of the resins, the extent of settling was estimated by comparing in the transverse direction of a resin-coated portion, and the molding processability was evaluated synthetically, including the extent of the formation of lines in a molten resin film, the occurrence of film breakage depending on the strength of the drawdown, flowability instability due to sagging, or Drawing honor and the like. The grading is as follows: O: good, Δ: slightly inferior, but acceptable in practice, x: inferior and unacceptable in practice.

Regarding the Procedure for assessing the degree of liability between the base paper and Resin layer of the polyethylene-type resin-coated resin Papiers, was a sample by peeling in their base paper layer and polyethylene layer, and it became the area percentage the proportion of base paper layer determined on the peeled polyethylene layer Adhesion strength between base paper and Resin layer was evaluated. The gradation is as follows: O: good (Area percentage: 100%), Δ: slight inferior liability, but acceptable in practice (area percentage: less than 100 and not less than 80%), x: low adhesion and not acceptable in practice (area percentage less than 80%).

The procedure for estimating a gel formed in melt extrusion of the resins was as follows: after the resins were made into a film for 8 hours under conditions of a predetermined temperature of 320 ° C and an extrusion speed of 2.5 kg / hr by gradation of the screw revolution speed; of the opening percentage of a breaker plate and the total mesh value of sieve packs were extruded according to the conditions shown in Table 15, the pieces of the formed gel of 0.1 mm or more in 0.01 m ^{2 of} the film were counted and their number compared with the initial number, thereby estimating the degree of formation of the gel. The gradation is as follows: ○: the number of pieces of the formed gel after 8 hours was the same as the initial number, ×: the number of pieces of the formed gel after 8 hours was larger than the initial number.

Regarding the Procedure for evaluating the fabrication properties of the a resin of polyethylene-type coated Papiers, were synthetically manufacturing properties rated, including Cuttability, based on the degree of fluffing on the cut surface of a formed by cutting with a commercial guillotine cutter Sample, including the abrasion resistance, based on the extent of formed scratches on the surface of the resin layer that generates were made by placing the resin layer surfaces of 2 arcs of the resin-coated paper overlaid and rubbed them together, including the nerve of the resin-coated one The grading is as follows: O: good, Δ slightly inferior, but acceptable in practice, x: inferior and unacceptable in practice.

Examples 36 to 41

It An experiment was carried out in the same manner as in Example 35, with the exception that the species and amounts of resins for the polyethylene resin composition in Table 14 or 15, respectively modified were. The results obtained are shown in Tables 15 and 16.

Table 14

Table 15

Table 16

Out The results shown in Table 15 clearly show that the a resin of polyethylene-type coated Papers by coating are produced under melt extrusion conditions, wherein the resin pressure higher at the screw end of the extruder as the value for the critical resin pressure (Examples 35 to 38), excellent, represent papers coated with a polyethylene-type resin, which contain no gel formed, and a good property image in moldability and adhesion between resin layer and Deliver base paper. In particular, it is clear that no Gel forms, even if the rotation speed is low Resin pressure but higher are the value of the critical resin pressure (Example 37).

is on the other hand, the resin pressure at the screw end of the extruder is higher than the value for the critical resin pressure (Examples 39 and 40) becomes gelation serious. Therefore, this is not desirable. Is the proportion of polyethylene high density more than 90 parts by weight (Example 40), unfavorable conditions in terms of gel formation, adhesion strength between the base paper and the resin layer and the moldability. This is therefore not desirable. is the high density polyethene MFR is less than 10 g / 10 min (Example 41), the fabrication properties are undesirably inferior.

By the present invention makes it possible to obtain an excellent, Polyethylene-type resin coated To provide paper, which gives good results in the shaping processability of his Resin layer and the adhesion strength between resin layer and base paper, the formation of a Gels in the resin layer is prevented.

Example 42

Mixed pulp of bleached sulfite hardwood pulp and bleached kraft-hardwood pulp in the ratio of 1: 1 was beaten to set its value for the Canadian Standard Freeness to 320 ml. Then, to 100 parts by weight of the pulp, 3 parts by weight of cationized starch, 0.2 part by weight of anionized polyacrylamide, 0.4 part by weight of alkylketene dimer emulsion (as ketene dimer) and 0.4 part by weight of polyamine-polyamide-epichlorohydrin Resin and it was made from paper with a basis weight of 160 g / m ² . The wet tissue thus obtained was dried at 110 ° C, then with an impregnating solution of 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of fluorescent whitening agent, 0.002 parts by weight of blue dye, 4 parts by weight of sodium chloride, 0.2 Parts by weight of citric acid and impregnated with 93 parts by weight of water to give an amount of 25 g / m ² , dried in hot air to adjust the water content of the finally obtained base paper to 8% by weight in the bone-dry state, and then at room temperature Linear pressure of 90 kg / cm for producing base paper for a backing for a picture-forming material supercalendered. The Bekk smoothness of the base paper in this case was 200 seconds.

Next, the side (the back side) of the base paper which represented the back side to the side on which an image-forming layer was formed by coating was subjected to corona discharge treatment, and thereafter to each resinous composition described in Table 17 with each polyethylene resin composition described in Table 17 of 25 microns at a resin temperature of 320 ° C and a running speed of the base paper of 150 m / min coated by melt extrusion. In the present case, a cooling roller having the ability to adjust the center-plane average roughness SRa of the surface of the first resin layer to the surface roughness shown in Table 17. The chill roll was designed so that its surface was roughened by a liquid honing process. Using this cooling roll, the melt extrusion coating process was carried out at a cooling water temperature of 12 ° C.

Subsequently, the front surface of the base paper was subjected to a corona discharge treatment and thereafter treated with a resin composition of 20 parts by weight titanium dioxide pigment masterbatch of 47.5 wt% low density polyethylene resin (density 0.920 g / cm ³ , MFR = 8.5 g / 10 minutes), of 50% by weight hydrated alumina (0.75% by weight as Al ₂ O ₃ , based on the weight of titanium dioxide) of surface-treated anatase titanium dioxide pigment and 2.5% by weight zinc stearate , and from 65 parts by weight of low density polyethylene resin (density 0.920 g / cm ³ , MFR = 4.5 g / 10 min) and 15 parts by weight of high density polyethylene resin (density 0.970 g / cm ³ , MFR = 7.0 g / 10 min) to a resin thickness of 32 microns at a resin temperature of 320 ° C and a peripheral speed of the base paper of 150 m / min by melt extrusion coated. The melt extrusion coating methods with polyethylene resin on the front and back were carried out by the so-called tandem method, with the extrusion coating methods being carried out one by one. In the present case, the surface of the titanium dioxide pigment-containing second resin layer of the resin-coated paper was processed into a glossy surface.

Then, the surface of the first resin layer of the resin-coated paper was subjected to a corona discharge treatment and then machine-coated with the following back-coating liquid. The backcoating liquid of colloidal silica and a styrene-based copolymer latex in a ratio of 1: 1 on a dry basis, which further contained a corresponding amount of 0.021 g / m ^{2 of} sodium polystyrenesulfonate and suitable amounts of a coating aid and the like, was used in an amount of 0.21 g / m ² , based on the latex (weighed as solids), to obtain a support for an image-forming material.

Regarding the Procedures for evaluating the molding processability of the Polyethylene resin composition for the first resin layer and the degree of gelatinous foreign matter in the first resin layer in the manner described above conducted Production method of the carrier pad for a Image-educational material as well as for the evaluation of the performance characteristics a sample obtained as a support for a Image-educational material, the reviews were with the now described Procedures performed.

Regarding the Procedure for evaluating the molding processability of the Polyethylene resin composition for the first resin layer in the production of the support for an image-forming material, The degree of sinking was estimated by looking at the corresponding Length in Transverse direction of a resin-coated portion on the back determined, and it was re synthetic aspects evaluated the molding processability, including the degree of formation of streaks in a molten resin film, the occurrence of film break, depending on the strength of the film Pulling down, an instability in flow behavior due to effervescence or Ziehresonanz and the like .. The gradation is as follows: O: good, Δ: slightly inferior, but acceptable in practice, X: inferior and unacceptable in practice.

Regarding the Approach to the estimation in melt extrusion of the polyethylene resin composition for the first resin layer formed chill roll spots, became the estimate made by looking at the extent of staining on the chill roll 6 hours after the start of production of the image-forming material visually assessed under the above production conditions. The Gradation is as follows: ❍: enough well, it was only a few chill roll spots formed, Δ: acceptable in practice, but formation of a slightly increased number of chill roll spots, x: unacceptable in practice, namely education of a large number of chill roll spots.

The method for estimating a gelatinous foreign matter formed in melt extrusion of the polyethylene resin composition for the first resin layer was as follows: after the composition was made into a film for 8 hours under conditions of a predetermined temperature of 320 ° C and an extrusion rate of 2.5 kg / hr extruded, the pieces of the formed gelatinous foreign matter of 0.1 mm or more in 0.01 m ^{2 of} the film were counted and their number compared with the initial number, whereby the degree of formation of gelatinous foreign matter was estimated. The gradation is as follows: ○: number of formed pieces of the gelatinous foreign matter after 8 hours was the same as the initial number, Δ the number of formed pieces of the gelatinous foreign matter after 8 hours is slightly higher forth as the initial number, but acceptable in practice; x: the number of formed pieces of the gelatinous foreign matter after 8 hours was much larger than the initial number and unacceptable in the field.

Regarding the Method for evaluating the cuttability of the backing for a Image-forming material, was the aforementioned color printing paper a length in the longitudinal direction of 11.7 cm cut with a precision pressure cutter, and the condition of the cut surface was evaluated. The gradation is as follows: ⊙: very good cuttability, namely almost no formation of whisker-like projections, ❍: good cutting ability, despite the formation of a small number of whisker-like projections; Δ: acceptable in practice, despite the formation of a somewhat larger number of whisker-like ones projections x: inferior cuttability and unacceptable in practice, namely Formation of a big one Number of whisker-like projections.

Regarding the procedure for evaluating the curling properties of the support for the image-forming material, the evaluation was made as follows. First, after a corona discharge treatment, the surface of the titania pigment-containing second resin layer of the image-forming support base was made green with a blue-sensitive emulsion layer containing a yellow coupler having an intermediate layer containing a color mixing inhibitor sensitive emulsion layer containing a magenta coupler having a UV absorbing layer containing a UV absorber, a red-sensitive emulsion layer containing a cyan coupler, and a protective layer, whereby a color printing paper containing gelatin in one Total amount of 8 g / m ² , was generated. Each color-sensitive emulsion layer contained silver chlorobromide in an amount corresponding to 0.6 g / m ² silver nitrate and further gelatin sufficient for the preparation, dispersion and film formation of silver halide, suitable amounts of an antifoggant, sensitizing dyes, a coating aid, a curing agent and a thickening agent. an appropriate amount of a filter dye and the like. Subsequently, the produced color printing paper was stored at 35 ° C and ordinary humidity for 5 days and then developed under color development, whereupon the curl condition of the resulting color print measuring 8.2 cm × 11 , 7 cm, was estimated. The grading is as follows: O: good enough corrugation properties, namely a slight minus corrugation (corrugation toward the backcoat layer) or shallow, Δ: acceptable in practice, however corrugation occurred to some extent, x: unacceptable in the field , because there was serious curling.

Regarding the Procedure for assessing the degree of liability between the base paper and first resin layer of the backing for a Image-educational material, each sample was added in a thermo-hygrostat 50 ° C and Stored 60% RH for 24 hours and then by peeling in the base paper layer and the resin layer is decomposed, and it becomes the area percentage of the portion determined on base paper layer, the at the peeled resin layer Sticking, causing the adhesion between the base paper and the back Resin layer was evaluated. The gradation is as follows: O: good (Area percentage: 100%), Δ: inferior liability, but acceptable in practice (area percentage: less than 100 and not less than 80%), x: inferior adhesion strength and not acceptable in practice (area percentage: less than 80%).

Tabelle 17 (Fortsetzung)

• (Anmerkung 1) HDPE: Polyethylenharz hoher Dichte mit einer Dichte von 0,967 g/cm³ und einer MFR von 15 g/10 min
• (Anmerkung 2) LDPE: Polyethylenharz niedriger Dichte mit einer Dichte von 0,924 g/cm³, einer MFR von 0,6 g/10 min, einem Prozentsatz an Molekülen mit dem Molekulargewicht von 500 000 oder mehr von 15 Gew.% und einem Wert für die kritische Schergeschwindigkeit von 0,06 s^–1.
• (Anmerkung 3) Zubereitungsverfahren desr Polyethylenharzzusammensetzungs-Kompound: das HDPE und LDPE wurden in der Form von Pellets eines Kompound-Harzes eingesetzt, welches durch vorheriges Vermischen in der Schmelze mit einem Extruder zum Kneten zubereitet war. Einfache Vermischung: das HDPE und LDPE wurden eingesetzt, indem man diese in einen Schmelzextruder in der Form einer durch einfaches Vermengen erhaltenen Mischung gab.
• (Anmerkung 4): Es ist die Zentrumsebene-Durchschnittsrauhigkeit SRa (μm) der Oberfläche der ersten Harzschicht der Trägerunterlage für das Bild-Bildungsmaterial angegeben, welche durch das in der vorliegenden Beschreibung spezifizierte Verfahren ermittelt wurde.

The results obtained are shown in Table 17. Table 17

Table 17 (continued)

• (Note 1) HDPE: High-density polyethylene resin having a density of 0.967 g / cm ³ and an MFR of 15 g / 10 min
• (Note 2) LDPE: Low-density polyethylene resin having a density of 0.924 g / cm ³ , an MFR of 0.6 g / 10 min, a percentage of molecules having a molecular weight of 500,000 or more of 15 wt% and a value for the critical shear rate of 0.06 s ^-1 .
• (Note 3) Preparation Method of the Polyethylene Resin Composition Compound: The HDPE and LDPE were used in the form of pellets of a compound resin prepared by previously melt-blending with an extruder for kneading. Simple mixing: the HDPE and LDPE were used by placing them in a melt extruder in the form of a blend obtained by simple blending.
• (Note 4): The center-plane average roughness SRa (μm) of the surface of the first resin layer of the image-forming support base sheet is determined, which was determined by the method specified in the present specification.

From the results shown in Table 17, it can be clearly seen that the underlays for an image-forming material (Sample Nos. 2, 3, 5 to 9 and 12) in which the center-plane average roughness SRa of the surface of the first resin layer is 0.6 to 2.0 μm, and the polyethylene resin in the first resin layer is a compound resin obtained by preliminarily melt-blending 90 to 65 parts by weight of high density polyethylene resin with 10 to 35 parts by weight of low density polyethylene resin according to the present invention is excellent carrier papers for an image-forming material, which have good moldability of the Polyetyhlenharzzusammensetzung, are free from chill roll stains, no contained gelatinous foreign matter and at the adhesion strength between base paper and resin layer, with corrugation properties and cuttability give a sufficiently good property picture. In particular, it can be clearly seen that, for the synthetic performance characteristics of the image forming support base member, the content ratio of the HDPE is preferably in the range of 85 to 70 parts by weight, and to improve the effect on the chill roll spots, the center plane average roughness SRa of the surface of the back resin layer Carrier pad for the image-forming material vorzugsweie in the range of 0.8 to 1.6 microns.

On the other hand the content of high density polyethylene resin exceeds 90 Parts by weight (Sample No. 1) is the moldability of the polyethylene resin composition Inferior, form a large number of chill roll spots as well as a big one Amount of gelatinous Foreign matter, and the adhesion between Base paper and resin layer is low. Therefore, this is not desirable. Is the share content of the high density polyethylene resin less than 65 parts by weight (Example No. 13), the curling properties are not good enough. This is therefore not desirable. Is only a simple mixing in the preparation of Polyethylene resin composition applied (No. 11), the molding processability and cuttability of the polyethylene resin composition is not good out, and it forms a large amount of gelatinous foreign matter from the early Beginning. Therefore, this is not desirable. In addition, if the center-plane average roughness SRa of the surface the first resin layer is less than 0.6 μm (Sample No. 4) is formed in unwanted Way a big one Number of chill roll spots. On the other hand, even if the center plane average roughness SRa of the surface of the first resin layer more than 2.0 μm is (sample No. 10), forms in undesirable Way a big one Number of chill roll spots.

In In this case, the problem of fogging was also caused, that everywhere on the opposite side surface on the front after winding the support for the image-forming material occurred.

Example 43

It became an experiment in the same way as in the case of No. 7 in Example 42 performed, with the exception that each Compound resin composition, in the same manner as in the case from No. 7 in Example 42, but using the table Polyethylene resins prepared as described in Table 1 19 indicated proportions instead of the coating the back in No. 7 in Example 42 used polyethylene resin composition was used. The results obtained are shown in Table 19.

Table 18

Table 19

From the results shown in Table 19, it can be clearly seen that the documents for the image-Bil (Samples Nos. 14 to 24) in which the polyethylene resin in the first resin layer is a compound resin composition prepared by melt-blending in advance from 90 to 65 parts by weight of high-density polyethylene resin having an MFR of 10 to 40 g 10 minutes and a density of 0.960 g / cm ³ or more with 10 to 35 parts by weight of low density polyethylene resin having an MFR of 0.2 to 2 g / 10 min and a density of 0.935 g / cm ³ or less, one Percentage of molecules having a molecular weight of 500,000 or more of 10% by weight or more and a value for the critical shear rate of 0.5 s ^-1 or less, wherein the value of the critical shear rate of the composition is 10 s ^-1 or less, are excellent base materials for an image-forming material, which have good moldability properties of the polyethylene resin composition, are free from chill roll stains, no formed Ge contain latent foreign matter and fail sufficiently well in terms of adhesion strength between base paper and resin layer, corrugation properties and cuttability.

In particular, it will be readily apparent that to prevent the formation of a gelatinous debris, the low density polyethylene resin is preferably one having an MFR of less than 1 g / 10 min. (See Sample Nos. 15 and 21 with Sample No. 22). The following is also clear: in terms of corrugation properties, the high density polyethylene resin is preferably one having a density of 0.962 g / cm ³ or more (See Samples Nos. 15 and 19 with Sample No. 20), and with respect to Moldability, preventive effect on the formation of a gelatinous foreign matter and the adhesion strength between the base paper and the resin layer is the high-density polyethylene resin preferably one having an MFR in the range of 10 to 30 g / 10 min (See Sample Nos. 15, 19 and 23 with sample No. 24). In addition, it is well understood that the compound resin composition used for practicing the present invention is preferably one having a value for the critical shear rate of less than 8 s ^-1 (See Samples Nos. 14 to 21 and 23 to Samples Nos 22 and 24).

On the other hand, if the MFR of the low-density polyethylene resin is more than 2 g / 10 min (Sample No. 27), the results on moldability and the degree of gelatinous foreign matter formation are not good. Therefore, this is not desirable. When the percentage of molecules having a molecular weight of 500,000 or more is less than 10% by weight (Sample Nos. 27 to 29), moldability is undesirably inferior and there is a tendency to form a large amount of gelatinous foreign matter. When the MFR of the high-density polyethylene resin is more than 40 g / 10 min (Sample No. 31), the results on moldability, gelatinous foreign matter-forming degree and adhesion strength between the base paper and the resin layer are not good. This is therefore not desirable. When the critical shear rate value of the compound resin composition is more than 10 s ^-1 (Sample Nos. 25 to 28 and 31), a large amount of gelatinous foreign matter unfavorably forms and a large number tends to be formed of chill roll spots.

By The present invention makes it possible to obtain an excellent Support base resin-coated paper type for an image-forming material to provide which chill rolls formed during production hardly yields and therefore is free from problems caused by the transfer the chill roll spots be produced, wherein the carrier pad in the first Resin layer on the back too the side on which an image-forming layer is formed should be, if necessary. contains not formed gelatinous foreign matter, and being a good grip between resin layer and base paper and a sufficiently good property picture having curl properties and cuttability and rapidly and can be stably produced.

Claims (14)

A resin-coated paper comprising a paper substrate and a first resin layer formed on one side of the paper substrate, said first resin layer comprising a polyethylene-type resin obtainable by melt blending of 90 to 65 wt High density polyethylene resin of 0.960 g / cm ³ or more, which has a melt index according to JIS K 6760 of 10.0 to 40.0 g / 10 min, with 10 to 35 parts by weight of low or medium density polyethylene resin of 0.935 g / cm ³ or less, which has a melt index according to JIS K 6760 of 0.2 to 2 g / 10 min, a percentage of molecules having a molecular weight of 500,000 or more of 10 wt% or more, and a value for the critical shear rate of 0.5 s ^-1 or less, the composition obtained by the melt blending having a value of the critical shear rate of 10 s ^-1 or less. A resin-coated paper according to claim 1, wherein the melt index Polyethylene resin of low or medium density 0.2 to 1 g / 10 min. A resin-coated paper according to claim 1, wherein the center-plane roughness SRa in the longitudinal direction the first resin layer is 0.6 to 2.0 μm, measured at a cut value of 0.8 mm with a three-dimensional surface-roughness meter of the sensor type. A resin-coated paper according to claim 1, wherein a second Resin layer containing a resin having film-forming properties the paper substrate on the back is formed to the side on which the first resin layer is trained. A resin-coated paper according to claim 4, wherein the film thickness nonuniformity is XX Rpy in the paper-forming direction of the paper substrate on one Side on which the second resin layer is formed, 140 mV or less. A resin-coated paper according to claim 4, wherein an image-forming layer is formed on the second resin layer. The resin-coated paper according to claim 6, wherein the image-forming layer is a photographic silver halide layer. A resin-coated paper according to claim 4, wherein the resin coating weight of the second resin layer is larger than that of the first resin layer by 3 g / m ² or more. The resin-coated paper according to claim 4, wherein the second Resin layer containing a titanium dioxide pigment. A resin-coated paper according to claim 4, wherein the resin with the film-forming properties is a polyolefin resin. The resin-coated paper according to claim 10, wherein the polyolefin resin is a polyethylene type resin. A process for producing a resin-coated paper by melt blending 90 to 65 parts by weight of high-density polyethylene resin of 0.960 g / cm ³ or more, which has a melt index according to JIS K 6760 of 10.0 to 40.0 g / 10 min having from 10 to 35 parts by weight of low or medium density polyethylene resin of 0.935 g / cm ³ or less, which has a melt index according to JIS K 6760 of 0.2 to 2 g / 10 min, a percentage of molecules having a molecular weight of 500 000 or more of 10 wt% or more and a critical shear rate value of 0.5 s ^-1 or less, and the resulting polyethylene type resin composition is melt-extruded to coat a base paper therewith, wherein said resin composition is obtainable by melt blending and has a critical shear rate value of 10 s ^-1 or less. A manufacturing method according to claim 12, wherein the resins of polyethylene type at a resin pressure at the screw end of an extruder be extruded in the melt, which is higher than the critical resin pressure. A manufacturing method according to claim 12, wherein the resins of the polyethylene type at a screw revolution speed extruded in the melt, which are higher than the critical rotation speed is.