JP3167822B2 - Method for producing polyethylene-based resin-coated paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin-coated paper in which one side of a paper substrate (hereinafter referred to as "base paper") is coated with a polyethylene resin. The present invention relates to an improvement in a method of extrusion-coating by preventing a resin layer from generating a gel when extrusion-coating a system resin.

[0002]

2. Description of the Related Art It is widely used to melt, extrude, and coat a resin capable of forming a film on a substrate such as paper, paperboard, cellophane, etc., and use the resin for food containers, packaging materials, release paper. Resin-coated papers such as printing papers, photographic supports and the like are well known.

[0003] When extruding and coating a molten polyethylene resin onto a base paper, the temperature is considerably higher than the melting point of the polyethylene resin. For example, the melting point of low-density polyethylene is around 105 ° C. to 110 ° C. and the melting point of high-density polyethylene is around 120 ° C. to 130 ° C., whereas the melt extrusion temperature by the T-die method is It is necessary to carry out at around 300 ° C. Generally, in a polyethylene molecule, in addition to linear carbon as a polymer of ethylene monomer, an unsaturated bond such as a carbon-carbon double bond, a methyl group, or a side having a carbon skeleton of a higher carbon atom bonded thereto. It is known to contain chain carbon.
For polyethylene, the temperature around 300 ° C is an appropriate temperature from the viewpoint of processing suitability, but it is within the range that promotes activation at the molecular level. As a result, radicals are likely to be generated near unsaturated bonds and side-chain carbons in the molecule, and the radicals undergo a chain reaction to cause a crosslinking reaction,
Often, when extruded as a film, they appear as gel-like defects. This gel becomes a projection on the surface of the resin-coated paper, impairs the appearance, and impairs various functions.

[0004] In a food container, printing paper, or the like, if a gel is present in the resin layer, there is a problem in that peeling due to poor printing at that portion or poor adhesion to the base paper occurs. In the case of release paper, the presence of gel often causes poor quality in the step of applying a release agent such as silicone on the resin layer. In particular, in the case of a photographic support, if the presence of the gel itself deteriorates the quality of the photographic image, or if a normal photographic image cannot be formed due to an obstacle at the time of emulsion coating, the commercial value of the photographic printing paper is lost. It often happens. For this reason, sufficient gel prevention measures must be taken.

As a method for preventing the generation of such a gel, there is a method of operating at a lower extrusion temperature, but in this case, the adhesiveness between the polyethylene resin and the paper is reduced, so that a necessary degree of adhesiveness is required. In order to maintain the above, the processing speed is limited, and the productivity is reduced.

Although it is effective to disassemble and clean the extruder in a short cycle, a reduction in productivity cannot be avoided.

On the other hand, in the production of a polyethylene resin film, an effect may be obtained by adding an antioxidant to prevent this gel. But,
In the case of extruding and coating a polyethylene-based resin on a base paper, addition of an antioxidant to prevent gelation is not generally performed so much as it deteriorates the adhesion between the substrate and the polyethylene-based resin.

In the case of release paper or the like in which the smoothness, heat resistance, abrasion resistance and the like of the resin layer are required, high density polyethylene having a high melting point is used for the resin layer. Molding processability such as flow instability due to the degree of surging or draw resonance and breakage of the film due to neck-in and draw-down properties is still insufficient. In particular, in the case of production under high-speed conditions in which the running speed of the base paper is 150 m / min or more, in addition to these problems, the adhesiveness between the resin layer and the base paper deteriorates, and the resin layer tends to peel off. Had a problem.

[0009] From the above points, no effective method for extrusion coating has been found so far in the production of polyethylene-based resin-coated paper so as to effectively prevent gel formation in the resin layer.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In producing a polyethylene resin-coated paper by an extrusion melt coating method, the present invention has been made without reducing productivity. It is an object of the present invention to provide an extrusion melting coating method which has good moldability of the resin layer and good adhesion between the resin layer and the base paper, and prevents gel formation in the resin layer.

[0011]

Means for Solving the Problems and Action As a result of extensive studies by the present inventors to solve the above-mentioned problems, a resin-coated paper is manufactured by extrusion-coating one side of a base paper with a polyethylene resin. In the method, when the polyethylene resin is melt-extruded from the extruder, the resin pressure at the tip of the screw of the extruder is melt-extruded at a resin pressure higher than the critical resin pressure (Pc). It was found that the purpose was achieved.

The critical resin pressure (Pc) is determined by the following method.

Pc = (Z · η · CSR) / (9.8 × 10 ⁵ · H) where Z is the screw development length,

## EQU4 ## where Pc is the critical resin pressure at the screw tip (Kgf /
cm ² ) η: viscosity of resin at 240 ° C (P) CSR: critical shear rate of resin (1 / sec) H: depth of screw groove at bottom of hopper (cm) n: screw pitch number D: barrel inner diameter (Cm) θ: Screw pitch angle (degree)

[0013] The critical shear rate (CSR) as used herein means:
Using a cone-plate type rotary viscometer (Rheometric Mechanical Spectrometer manufactured by Rheometrics, cone-plate diameter: 25 mm, angle: 0.1 rad) at 240 ° C. The shear rate at the point where the measured shear stress and the first normal stress difference become equal.

As is apparent from the above formula, the resin pressure at the tip of the screw of the extruder used in the present invention can be easily determined by measuring the viscosity and critical shear rate of the extruder used for extrusion coating and the raw polyethylene resin. You can ask.

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

As a method for increasing the resin pressure, a method using a resin having a low melt flow rate (hereinafter, simply referred to as MFR) specified by JIS K 6760 as far as the invention permits, a die lip opening method, and the like. A method of reducing the degree of opening, a method of reducing the opening area of the breaker plate in the extruder, a method of inserting a screen pack into the resin flow path in the extruder, a method of increasing the number of screen packs, A method using a screen pack having a large number of meshes may be used. These methods may be used alone or in combination of two or more.

In practice, it is preferable that the critical resin pressure be small in order to widen the operating range during extrusion melt coating.
As a method of reducing the critical resin pressure, a method using a resin having a viscosity or a critical shear rate as low as possible within the range permitted by the present invention, a method of deepening a screw groove at a lower portion of a hopper, and a method of shortening a screw development length are used. Although a method etc. are mentioned, these methods can be used alone or in combination of two or more.

Further, when the operation is performed with the rotation speed of the extruder lowered by cleaning the die slip, switching the resin, or the like, gel may be generated and hindrance may occur. When the resin pressure is equal to or higher than the critical resin pressure, generation of gel can be suppressed.

To extrude and coat the polyethylene resin melt-extruded from the die of the extruder onto the base paper, the base paper may be directly extrusion-coated, or the adhesive strength between the base paper and the polyethylene resin may be obtained. The surface of the base paper may be subjected to a known surface activation treatment such as a corona discharge treatment, a flame treatment, an anchor coat treatment or the like, and then subjected to extrusion coating.

The extrusion coating can be performed by using a known method and apparatus. For example, a polyethylene resin is extruded from a die of an extruder at a resin temperature of 280 to 340 ° C. to form a molten thin film, and the molten thin film is pressed. Rolling, while the adhesive surface is untreated or subjected to the above-mentioned surface activation treatment and extrusion-coated through the base paper, the pressing roll, and the cooling roll which are also guided to the pressing roll. It is performed by

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

As the polyethylene resin used as the resin layer in the present invention, high density polyethylene, low density polyethylene or medium density polyethylene is used.

The high-density polyethylene resin of the resin layer used in the practice of the present invention includes JIS K 6760.
The melt flow rate (hereinafter simply referred to as MFR)
) Is 10.0 g / 10 min to 40.0 g / 10 min, and if the density is in the range of 0.950 g / cm ³ or more, various MFRs, densities, molecular weights, molecular weight distributions, etc. These can be used alone or as a mixture, and various materials such as ordinary high-density polyethylene resins, copolymers of ethylene with α-olefins such as propylene and butylene, and mixtures thereof can be used. If the MFR is less than the above, the adhesion between the base paper and the resin layer and the formability are reduced. If the MFR is larger than the above, the mixing property and the formability of the resin are undesirably reduced. Further, when the density is less than the above, the secondary workability such as the cutting property is reduced, which is not desirable.

The low-density polyethylene or medium-density polyethylene resin has an MFR of 0.2 g.
/ 10 min to 4.0 g / 10 min and a density of 0.
Various MFRs, densities, molecular weights, molecular weight distributions as long as the fraction is 935 g / cm ³ or less, the molecular weight is 500,000 or more, the fraction is 8% by weight or more, and the critical shear rate is 20.0 (1 / sec) or less. Can be used alone or as a mixture. For example, high-pressure low-density polyethylene resin (autoclave low-density polyethylene resin, tuber low-density polyethylene resin, etc.), linear low-density polyethylene Various resins such as resins, medium-density polyethylene resins, copolymers of ethylene with α-olefins such as propylene and butylene, carboxy-modified polyethylene resins and mixtures thereof can be used. If the MFR is less than the above, the mixing property of the resin, the adhesiveness between the base paper and the present resin layer, and the moldability are deteriorated. If the MFR is greater than the above, the moldability is decreased.
If the density is higher than the above, the adhesiveness between the base paper and the resin layer,
It is not desirable because the formability and the like are reduced. The fraction of the resin having a molecular weight of 500,000 or more is 8% by weight or more, preferably 10% by weight or more, more preferably 12% by weight or more.
% By weight or more. If the fraction of the resin having a molecular weight of 500,000 or more is less than 8% by weight, molding processability, particularly neck-in, becomes large, which is a problem. Here, the measurement of molecular weight is carried out by
Turs 150-C (column: GMH-X manufactured by Tosoh Corporation)
LHT 8mmφ × 30cm × 3, solvent: 1,2,2
4-trichlorobenzene, temperature: 135 ° C, flow rate: 1 m
/ Min) by the GPC method. Next, the critical shear rate of the resin is 20.0 (1 / sec) or less, and preferably 10.0 (1 / sec) or less. If the critical shear rate is higher than 20.0 (1 / sec), there is a problem in molding processability, gel generation and the like. Here, the critical shear rate was measured using a cone-plate type rotary viscometer (Rheometric Mechanical Spectrometer manufactured by Rheometrics Inc., cone-plate diameter: 25 mm, angle: 0). .1r
ad, temperature: 240 ° C.), and the shear rate at the point where the difference between the shear stress and the first normal stress was equal was defined as the critical shear rate.

The ratio of the high-density polyethylene resin and the low-density polyethylene resin or the medium-density polyethylene resin used in the practice of the present invention, the MFR, the density and the critical shear rate are as follows. The mixing processability, moldability and adhesion between the base paper and the resin composition layer of the polyethylene-based resin-coated paper, the effect of preventing gel formation, and the secondary processing properties such as the cutting properties and ease of handling of the resin-coated paper. As a result of trial and error experiments, it was determined from a comprehensive point of view, and the present invention has been achieved. In particular, the amount of the high-density polyethylene resin used is 95 parts by weight or more.
50 parts by weight, preferably in the range of 85 parts by weight to 65 parts by weight. If the amount of the resin is less than 50 parts by weight, the rigidity of the resin layer is reduced, and the secondary workability such as the cutting property of the resin-coated paper is deteriorated. There is a problem in that the mixing property, moldability, adhesiveness between the base paper and the resin layer and the like are deteriorated.

The polyethylene resin of the resin layer used in the practice of the present invention is used as a compound resin prepared by melt-mixing in advance. As a method for preparing a compound resin by previously melting and mixing a high-density polyethylene resin and a low-density polyethylene resin or a medium-density polyethylene resin, a simple melt mixing method, a multi-stage melt mixing method, or the like can be used. For example, a Banbury mixer, a pressure kneader, a heating roll kneader, an extruder, a twin screw extruder and the like can be used. If a polyethylene resin is not used as a compound resin, but is directly mixed into a melt coating extruder in the state of dry mixing and extrusion coating is applied, the adhesiveness between the base paper and the resin layer, the mixing properties of the resin, and molding This is a problem because workability and the like deteriorate.

In the present invention, the critical shear rate of the resin is not particularly limited within the range of the polyethylene resin in order to prevent a stagnant gel which is generated with time during extrusion melt coating. / S) or less, preferably 15 (1 / s) or less. When the critical shear rate is more than 30 (1 / second), the critical resin pressure for preventing the generation of gel becomes large, which may be practically difficult. The prevention of gel generation according to the present invention is considered to be caused by the viscoelastic properties of the resin at a high resin temperature during melt extrusion coating, and by setting the resin pressure at the screw tip to a critical resin pressure or higher. It is considered that this was caused by a reduction in the chance of gelation, an improvement in gel pulverization and kneading, and the like.

The configuration of the resin layer of the resin-coated paper in the present invention may be either a single layer or a multilayer of two or more layers. Also in this case, the polyethylene resin of the present invention can be used. Further, the respective layers of the multilayer may have different compositions or the same composition. As a method for forming a resin layer composed of multiple layers, any of a coextrusion melt coating method and a sequential extrusion melt coating method may be adopted.

In each of the resin layers of the polyethylene resin-coated paper of the present invention, white pigments such as titanium dioxide, zinc oxide, talc, calcium carbonate, stearamide, arachidine, etc. are contained as long as the effects of the present invention are not impaired. Fatty acid amides such as acid amide, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate,
Fatty acid metal salts such as calcium palmitate, hindered amines, phosphorus-based, sulfur-based antioxidants, various types of antioxidants such as cobalt bull, gunjo, celianble, and phthalocyanine bull; Magenta pigments and dyes such as fast violet and manganese violet, fluorescent brighteners, ultraviolet absorbers,
Various additives such as an antistatic agent and a lubricant can be appropriately contained. These additives are added in advance to the high-density polyethylene resin and the low-density polyethylene resin or the medium-density polyethylene resin to be used, or added at the time of melt mixing, or a so-called master batch added to the resin at a high concentration in advance. The masterbatch may be made and added to the resin during melt extrusion coating.

The base paper used in the practice of the present invention is a conventional paper.
Natural pulp paper containing natural pulp as a main component (hereinafter referred to as natural pulp)
The base paper mainly composed of rup paper is simply referred to as base paper. )
Is preferred. In addition, natural and synthetic pulp, synthetic fiber
Mixed paper, synthetic pulp, synthetic fiber or synthetic
So-called synthetic paper made of a resin film may be used. Also, the base paper
There is no particular limitation on the thickness of the paper, but its basis weight is 40 g.
/ M^Two ~ 250g / m ^Two Are preferred.

The pulp constituting the base paper preferably used in the practice of the present invention is described in JP-A-58-37642 and JP-A-58-37642.
It is advantageous to use appropriately selected natural pulp as described or exemplified in JP-A-67940, JP-A-60-69649 and JP-A-61-35442. Natural pulp was subjected to ordinary bleaching treatment of chlorine, hypochlorite, chlorine dioxide bleaching, and alkali extraction or alkali treatment and, if necessary, oxidative bleaching treatment with hydrogen peroxide, oxygen, etc., and a combination treatment thereof. Wood pulp of softwood pulp, hardwood pulp, and softwood pulp mixed pulp is advantageously used, and various pulp such as kraft pulp, sulfite pulp, and soda pulp can be used.

The base paper preferably used in the practice of the present invention may contain various additives at the time of preparing the stock slurry. As sizing agents, fatty acid metal salts, fatty acids, alkyl ketene dimer emulsions or epoxidized higher fatty acid amides, alkenyl or alkyl succinic anhydride emulsions described or exemplified in JP-B-62-7534,
As a dry paper strength enhancer such as rosin derivative, anionic,
Cationic or amphoteric polyacrylamide, polyvinyl alcohol, cationized starch, vegetable galactomannan, etc., polyamine polyamide epichlorohydrin resin as a wet paper strength enhancer, etc., as filler, clay, kaolin, calcium carbonate, titanium oxide, etc. Water-soluble aluminum salts such as aluminum chloride and bansulfate as fixing agents; caustic soda, sodium carbonate, sulfuric acid and the like as pH adjusters; and others, JP-A-63-204251 and JP-A-1-1-266537. It is advantageous to incorporate color pigments, coloring dyes, optical brighteners and the like described or exemplified in the above items in appropriate combinations.

In the base paper preferably used in the practice of the present invention, various water-soluble polymers, antistatic agents, and additives can be contained by a spray or tab size press. As a water-soluble polymer, JP-A-1-
As starch-based polymers, polyvinyl alcohol-based polymers, gelatin-based polymers, polyacrylamide-based polymers, cellulosic-based polymers, gelatin-based polymers, etc. described or exemplified in No. 266537, chlorides as antistatic agents Sodium, alkali metal salts such as potassium chloride, alkaline earth metal salts such as calcium chloride and barium chloride, colloidal metal oxides such as colloidal silica, organic antistatic agents such as polystyrene sulfonate, emulsion, latex, Petroleum resin emulsions, pigments such as clay, kaolin, talc, barium sulfate, titanium oxide, etc .; pH regulators such as hydrochloric acid, phosphoric acid, citric acid, caustic soda, etc.
In addition, it is advantageous to incorporate additives such as the above-mentioned coloring pigments, coloring dyes, and optical brighteners in an appropriate combination.

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

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Example 1 MFR 15.0 g / 10 min, density 0.967 g / c
high-density polyethylene 70 parts by weight of m ³ and MFR0.6g
/ 10 min, density 0.924 g / cm ³ , molecular weight 50
15% by weight or more with a critical shear rate of 0.06
(1 / second) of 30 parts by weight of low-density polyethylene was melt-mixed in advance, and the mixture was extruded at a resin temperature of 320 ° C. from an extruder to a basis weight of 1
It was prepared by extrusion coating a 70 g / m ² highly smooth paper to a thickness of 25 μm.

As a method for evaluating the moldability during melt extrusion coating of a resin, the length of the resin-coated portion in the lateral direction is measured to evaluate the degree of neck-in, and the degree of occurrence of streaks in the molten resin film. In addition, the moldability was evaluated comprehensively in terms of the occurrence of film breakage due to the degree of drawdown, the instability of flow due to surge or draw resonance, and the like. The evaluation criteria are as follows: 良好: good, Δ: slightly bad, but no practical problem, x: bad, practically problematic to some extent.

As a method for evaluating the adhesiveness between the base paper and the resin layer of the polyethylene-based resin-coated paper, the sample was peeled into the base paper layer and the polyethylene layer, and the area ratio of the base paper layer adhered to the peeled polyethylene layer was determined. Was measured to evaluate the adhesiveness between the base paper and the resin layer. Evaluation criteria are as follows: ○: good at 100% area ratio, Δ: 80% at less than 100% area ratio
Above, the adhesiveness is somewhat poor but there is no practical problem. X: The area ratio is less than 80%, which indicates that the adhesiveness is poor and there is some practical problem.

As a method for evaluating the gel at the time of melt extrusion of the resin, the screw rotation speed, the opening ratio of the breaker plate, and the total mesh number of the screen pack are changed so as to satisfy the conditions shown in Table 2. 0.1 mm in a 0.01 m ² film after extruding into a film for 8 hours under the conditions of a set temperature of 320 ° C. and an extrusion amount of 2.5 kg per hour.
The gel was evaluated by measuring the number of the above gels and comparing with the initial value. As evaluation criteria, ○: the number of gels after 8 hours does not change from the initial value. X: The number of gels after 8 hours increased from the initial value.

As a method for evaluating the secondary workability of the polyethylene-based resin-coated paper, the cutability of the sample cut with a commercially available guillotine cutter was evaluated by the degree of fluffing, and the resin layer surface of the resin-coated paper was evaluated. Comprehensive evaluations were made on the abrasion resistance depending on the degree of scratches on the resin layer surface and the secondary workability such as the stiffness of the resin-coated paper when they were rubbed together. The evaluation criteria are as follows: 良好: good, Δ: slightly bad, but no practical problem, x: bad, practically problematic to some extent.

[0040] Example 2-5, and, changing the Comparative Example 1 to 2 polyethylene resin composition on the resin type and proportion shown in Table 1, Table 2, were carried out in the same manner as in Example 1.

[Table 1] Tables 2 and 3 show the obtained results.

[0041]

[Table 2]

[0042]

[Table 3] From the results in Tables 2 and 3 , it can be seen from the results that the resin pressure at the tip of the screw of the extruder according to the present invention is polyethylene resin-coated paper coated under melt extrusion conditions in which the resin pressure is equal to or higher than the critical resin pressure (Examples 1 to 3).
It can be clearly understood that 5 ) is an excellent polyethylene-based resin-coated paper which does not generate gel and has good moldability and good adhesion between the resin layer and the base paper. In particular, even when the rotational speed is low, even when the resin pressure is higher than the critical resin pressure (Example 3), no gel is generated. Example 5 shows the extruder screen.
Melt extrusion where the resin pressure at the tip of the screw is higher than the critical resin pressure
Since the conditions are satisfied, no gel is generated and molding processing
And the adhesiveness between the resin layer and the base paper is good. That is,
All the effects of Ming have been achieved. But used high
MFR of low density polyethylene is less than 10g / 10min
Therefore, there is a problem in secondary workability.

On the other hand, it is understood that the samples other than the present invention shown in Comparative Examples 1 and 2 have problems. When the resin pressure at the tip of the screw of the extruder is lower than the critical resin pressure (Comparative Examples 1 and 2), the gel is poor and is a problem. The resin pressure at the extruder screw tip is critical resin pressure
When the content is too small and the content of the high-density polyethylene is more than 95% by weight (Comparative Example 2), there is a problem that the adhesion between the gel, the base paper and the resin layer and the moldability are poor.

[0044]

According to the present invention, an excellent polyethylene-based resin coating having good moldability and processability of the resin layer, good adhesion between the resin layer and the base paper, and capable of preventing gelation of the resin layer. Can supply paper.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kohei Nitta 3-10, Ushidori, Kurashiki-shi, Okayama Pref. Mizushima Plant, Mitsubishi Kasei Co., Ltd. (72) Inventor Tetsuya Ashida 3-4-2 Marunouchi, Chiyoda-ku, Tokyo No. Mitsubishi Paper Mills Co., Ltd. (72) Inventor Osamu Kojima 3-4-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Paper Mills Co., Ltd. (72) Yuichi Morita 3-4-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Paper Mills (56) References JP-A-60-150049 (JP, A) JP-A-60-35728 (JP, A) JP-A-58-95732 (JP, A) JP-A-49-119958 (JP, A A) Fully open sho 59-149944 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 D21H 11/00-27/42 B29C 47/00- 47/96 JICST file (JOIS)

Claims (3)

(57) [Claims] In a method for producing a polyethylene resin-coated paper by extruding and coating a polyethylene resin on one side of a paper substrate, when a polyethylene resin is melt-extruded from an extruder, a screw tip of the extruder is used. A method for producing a polyethylene-based resin-coated paper, wherein a polyethylene-based resin is melt-extruded at a resin pressure at or above a critical resin pressure. The critical resin pressure (Pc) (Kgf / cm ² ) here is defined by the following equation. Pc = (Z · η · CSR) / (9.8 × 10 ⁵ · H) where Z is the screw development length, and Z = π · n · D / cos θ Medium, Pc: Critical resin pressure at the screw tip (Kgf /
cm ² ) η: viscosity of resin at 240 ° C (P) CSR: critical shear rate of resin (1 / sec) H: depth of screw groove at bottom of hopper (cm) n: screw pitch number D: barrel inner diameter (Cm) θ: Screw pitch angle (degree) 2. The polyethylene resin according to JIS K6.
The melt flow rate specified in 760 is 10.0 g /
10 minutes to 40.0 g / 10 minutes, density 0.950 g / c
It is m ³ or more high-density polyethylene resin 95 parts by weight to 5
In 0 weight parts, the melt flow rate specified in JIS K 6760 is 0.2 g / 10 min to 4 g / 10 min, the density is 0.935 g / cm ³ or less, and the fraction of molecular weight 500,000 or more is 8 wt. % Or less and a critical shear rate of 20.0 (1 / second) or less, a resin obtained by melt-mixing a polyethylene resin composition comprising 5 to 50 parts by weight of a low-density polyethylene resin or a medium-density polyethylene resin. 2. A method for producing a polyethylene resin-coated paper according to claim 1. 3. A low-density polyethylene resin or a medium-density polyethylene resin having a melt flow rate defined by JIS K 6760 of 0.2 g / 10 min to less than 1 g / 10 min. PROCESS FOR PRODUCING POLYETHYLENE RESIN-COATED PAPER