JP2008297666A - Base paper for impregnation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base paper for impregnation, containing a wood pulp as a main raw material, and having excellent impregnating ability and cutting suitability. <P>SOLUTION: The base paper for the impregnation comprising a multilayer composed of at least two or more layers is obtained by using the whole raw material pulp containing 80-100 mass% of needle-leaved tree pulp formulated in the whole raw material pulp, and 2-20 mass% of thermally expandable particles based on the pulp solid components in the whole raw material pulp, and has 700-1,400 μm paper thickness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an impregnating base paper, and more particularly, to an impregnating base paper that is excellent in impregnation properties of chemicals and the like and cut suitability and is mainly used as a carrier for insect repellents.

  For example, a carrier for an insect repellent for clothes shown in Patent Document 1 is a base paper for impregnation using cotton linter pulp, which is a non-wood pulp having a high liquid absorbency, in order to absorb a predetermined amount of a drug such as a liquid insect repellent. Is used. Such impregnating base paper is cut into a predetermined size after impregnating the chemical, but since cotton linter pulp is used, there is a lot of whisker-like fluff from the cut portion, and the cut suitability is poor. was there. In addition, such a fluffed impregnating base paper also has a problem in that it looks as if it is a low-quality inferior product because the appearance deteriorates.

  In addition, the base paper for impregnation used for such a carrier such as an insect repellent needs to have a low density in order to have a liquid absorption property of a medicine or the like, that is, impregnation property of the medicine or the like. However, the base paper for impregnation, which uses cotton linter pulp and has a lower density, is more prone to fluff on the cut surface and more likely to generate paper dust. There was a problem of doing. That is, since the impregnation property and cut suitability of the drug are contradictory properties, it is difficult to satisfy both.

  In addition, as shown in, for example, Patent Documents 2 to 7 and the like, heat foamable particles are contained in a raw pulp that does not use cotton linter pulp, and heated to foam the heat foamable particles, thereby reducing the density. Paper has been proposed. However, the portion of the low-density paper that has been reduced in density by the expansion of the heat-expanded particles cannot obtain a sufficient gap between the pulp fiber and the heat-expandable particles, and therefore has an extremely high ability to absorb the drug. It was low and difficult to use as a carrier for the above-mentioned insect repellent for clothes.

JP-A-7-203822 Japanese Patent Laid-Open No. 2002-20996 JP-A-8-92898 JP-A-7-243196 JP-A-5-339898 JP 2003-105693 A JP-A-8-226097

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a base paper for impregnation which uses wood pulp as a main raw material and is excellent in drug impregnation property and cut suitability.

  The object of the present invention is a base paper for impregnation composed of at least two or more layers, wherein 80-100% by mass of softwood kraft pulp is blended in the total raw pulp, and the thermally foamable particles in the total raw pulp It is achieved by providing a base paper for impregnation characterized by containing 2 to 20% by mass in terms of solid content with respect to the pulp solid content and having a paper thickness of 700 to 1400 μm.

  In addition, the above-mentioned object of the present invention is characterized in that the impregnating base paper is adjusted to 600 to 760 ml in freeness of pulp fibers disaggregated according to JIS P-8220 (based on JIS-P8121). This is achieved effectively by providing the impregnating base paper.

  Furthermore, the above-mentioned object of the present invention is based on JAPAN TAPPI No. In accordance with “Paper—Absorptivity Test Method—Part 2: Dropping Method” described in 32-2, JAPAN TAPPI No. This is achieved more effectively by providing a base paper for impregnation characterized in that the liquid absorption measured using the test solution of kit number 6 described in 41 is 1 to 16 seconds.

  According to the base paper for impregnation according to the present invention, the main raw material is softwood kraft pulp, which is a wood pulp, and by containing thermally foamable particles in the raw material pulp, the impregnation property of a medicine or the like is high and excellent. It has cut aptitude.

  Hereinafter, the base paper for impregnation according to the present invention will be described in detail with reference to the drawings, taking as an example the case of three paper layers of a surface layer, an intermediate layer, and a back layer. Note that the base paper for impregnation according to the present invention is not limited to the following embodiment, and it is needless to say that the configuration can be changed as appropriate without departing from the scope of the claims.

  The base paper for impregnation according to the present invention is composed of three paper layers, a surface layer, an intermediate layer, and a back layer, and 80 to 100% by mass of softwood kraft pulp is blended in the total raw pulp, and this total raw pulp A raw material pulp slurry containing 2 to 20 mass% of thermally foamable particles in terms of solid content with respect to pulp solid content is used, and the paper thickness is set to 700 to 1400 μm. Thereby, even if it does not mix | blend the cotton linter pulp which is non-wood pulp, the impregnation property of the chemical | medical agent more than equivalent to the paper which mix | blended the cotton linter pulp abundantly can be obtained, without cut suitability falling. Further, by configuring the impregnating base paper according to the present invention in this way, the synthetic resin emulsion in the outer shell of the thermally foamable particles strengthens the bond between the pulp fibers, thereby reducing the cutting suitability of the impregnating base paper. It can be suppressed more.

  Examples of raw pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), conifer unbleached kraft pulp (NUKP), hardwood semi-bleached kraft pulp (LSBKP), and conifer Semi-bleached kraft pulp (NSBKP), chemical pulp such as hardwood sulfite pulp, softwood sulfite pulp, stone grand pulp (SGP), pressurized stone grand pulp (PGW), refiner grand pulp (RGP), thermo ground pulp (TGP), Chemical pulp such as Chemi-Grand Pulp (CGP), Ground Pulp (GP), Thermomechanical Pulp (TMP) Kent waste paper, imitation waste paper, Produced chemically or mechanically from disaggregated waste paper pulp, disaggregated / deinked waste paper pulp, or disaggregated / deinked / bleached waste paper pulp, or non-wood fibers such as kenaf, hemp, straw, etc. Various well-known pulps such as fresh pulp can be used.

  However, the raw material pulp used for the base paper for impregnation according to the present invention has a long fiber length and is 80% by mass or more, preferably 90% by mass or more, most preferably 95% of softwood kraft pulp (NKP) which is a rigid pulp fiber. It is contained by mass% or more. The conifer kraft pulp may be virgin pulp or conifer kraft pulp derived from waste paper.

  As a result, the heat-expandable particles contained in the raw material pulp are expanded by heating, and voids are formed between the pulp fibers and between the heat-expandable particles and the pulp fibers. Therefore, the predetermined quality (impregnation property of the drug) of the present application can be obtained. In addition, since wood pulp is used as the main raw material, it is superior in cut suitability as compared with a base paper for impregnation using cotton linter pulp, so that it has good workability and can be manufactured at low cost.

  In addition, even if the fiber length is short and the raw material pulp containing a large amount of soft hardwood pulp or the like is used, the heat-expandable particles are contained in the raw material pulp, and adjusted to a predetermined density, Since sufficient gaps are not obtained between the pulp fibers or between the heat-expandable particles and the pulp fibers, liquid absorbency (drug impregnation property) such as a predetermined drug cannot be obtained.

  Moreover, if the blending ratio of the softwood kraft pulp is less than 80% by mass, sufficient voids cannot be secured in the paper even when the thermally foamable particles are foamed. It becomes difficult.

  Furthermore, the raw pulp used for the base paper for impregnation according to the present invention has a Canadian standard freeness (CSF) measured according to JIS P 8121 of a pulp fiber disaggregated according to JIS P 8220 of 600 to 760 ml. , Preferably 650 to 760 ml, most preferably 680 to 750 ml. Thereby, chemical | medical agents, such as an insect repellent, can be impregnated in a predetermined amount with a gravure printing machine etc. within a predetermined time, and cut suitability in a subsequent processing step can be imparted. That is, the balance between the impregnation property and the cut suitability, which are contradictory properties, can be improved. When the freeness (CSF) is less than 600 ml, sufficient voids cannot be formed in the impregnating base paper even if heat-expandable particles are contained in the raw pulp, and a predetermined liquid absorbency (chemical) Cannot be ensured. On the other hand, when the freeness (CSF) exceeds 760 ml, although it is excellent in terms of providing voids in the impregnating base paper, the entanglement between pulp fibers becomes weak, so the cut suitability deteriorates, and delamination after cutting Prone to problems.

  The raw pulp is adjusted so that the weight average fiber length is 2.0 to 2.7 mm, preferably 2.3 to 2.7 mm. The weight average fiber length was measured with “Fiber Quality Analyzer” manufactured by OpTest Equipment. The fiber length of cotton linter pulp is 2 to 12 mm.

  Moreover, in the raw material pulp of the base paper for impregnation according to the present invention, the thermally foamable particles are 2 to 20% by mass, preferably 3 to 10% by mass, more preferably 3 to 10% by mass in terms of solid content with respect to the pulp solid content. 6% by mass is contained. Thereby, since the space | gap between pulp fibers can be expanded and the density of the base paper for an impregnation can be lowered | hung, a water absorption and a liquid absorptivity improve, ie, the impregnation property of a chemical | medical agent can be improved.

  In addition, if the content of the heat-expandable particles is less than 2% by mass, the pulp fibers cannot be sufficiently expanded even if the heat-expandable particles are foamed, and a predetermined density may be obtained. It becomes difficult. On the other hand, even if the content of the heat-expandable particles is more than 20% by mass, improvement in liquid absorbency (drug impregnation) cannot be expected, and only the production cost increases. Furthermore, since the problem of a decrease in interlayer strength due to the inclusion of thermally foamable particles becomes greater, there arises a problem that delamination is likely to occur from a cross section or a corner during cutting.

  As the thermally foamable particles, particles in which a low boiling point solvent is sealed in a fine particle outer shell made of a thermoplastic synthetic resin can be used. The heat-expandable particles have a volume average particle diameter of 5 to 30 μm, and expand by 4 to 5 times in diameter and 50 to 130 times in volume when heated at 80 to 200 ° C.

  Examples of the thermoplastic synthetic resin constituting the outer shell include copolymers such as vinylidene chloride, acrylonitrile, acrylic acid ester, and methacrylic acid ester. Examples of the low boiling point solvent enclosed in the outer shell include isobutane, pentane, petroleum ether, hexane, low boiling point halogenated hydrocarbon, and methylsilane.

  Examples of such thermally expandable particles include “Matsumoto Microsphere F-20 Series”, “F-30 Series”, “F-36 Series”, and “F-46 Series” manufactured by Matsumoto Yushi Seiyaku Co., Ltd. "Expancel WU" and "Same DU" sold by Nippon Philite Co., Ltd. can be used, but the thermally foamable particles used in the base paper for impregnation according to the present invention are not limited to these.

  However, since the temperature of the paper drying step is generally about 130 ° C., in the impregnating base paper according to the present invention, the low temperature expansion type in which the expansion start temperature of the thermally expandable particles is 90 to 130 ° C. is preferable.

  Thermally foamable particles are heated above the softening point of the thermoplastic synthetic resin that constitutes the outer shell, and at the same time, the low-boiling solvent encapsulated is vaporized, the vapor pressure rises, the outer shell expands, and the particles expand. During expansion, the internal pressure and the shell tension / external pressure are balanced to maintain the expanded state. The thermally foamable particles are generally expanded to this state and used as a lightening agent, a bulking agent, a cushioning agent, a heat insulating agent and the like. However, when heat is further applied to the expanded thermally expandable particles, that is, when excessive heat is applied, gas permeates and diffuses from the expanded and thin shell, and the shell expands more than the internal pressure. Tension and external force increase, and the foamed particles shrink.

  Since the heat-expandable particles used in the base paper for impregnation according to the present invention are foamed by a dryer in the drying process, for this reason, low-temperature expansion type heat-expandable particles having an expansion start temperature of 90 to 130 ° C. are used. Is preferred. That is, if the expansion start temperature is a thermally foamable particle of less than 90 ° C., the once expanded particle contracts again, and a predetermined void cannot be secured, so that the desired drug impregnation property of the present application is achieved. Can't get.

  Moreover, since the voids are formed in the layer containing the heat-expandable particles, the liquid absorption (water absorption) property becomes high. Therefore, when impregnated with an insect repellent agent or the like as in the impregnated base paper and then dried, the paper greatly expands and contracts and wrinkles are generated on the surface of the impregnating base paper.

  Therefore, it is preferable to make the contents of the heat-expandable particles in the surface layer and the back layer substantially the same amount, thereby improving the impregnation property of the drug and the cutability at the time of processing. When impregnated and processed into an insect repellent carrier, etc., it is preferable in that the paper curl and wrinkles are less likely to occur during use of the insect repellent carrier after the impregnating base paper is processed.

  Furthermore, when the impregnating base paper according to the present invention is formed by combining three or more layers, it is more preferable that each layer contains approximately the same amount of thermally foamable particles.

  That is, in order to obtain a predetermined liquid absorbency (drug impregnation property), when the heat-expandable particles are contained only in the surface layer and the back layer, or when the content of the heat-expandable particles in the surface layer and the back layer is increased, There is a risk that the cutting suitability of this will be reduced. Therefore, in the base paper for impregnation, which is rarely subjected to offset printing or the like that requires surface strength, it is more preferable that each layer contains approximately the same amount of thermally foamable particles.

  Moreover, it is preferable to use a fixing agent because the thermally foamable particles do not self-fix. As this fixing agent, polyacrylamide type paper strength agent, polyamide epichlorohydrin type paper strength agent, polyethyleneimine type paper strength agent, starches such as starch, oxidized starch, carboxymethylated starch, plant gum, polyvinyl alcohol, Various known materials such as carboxymethyl cellulose can be used.

  Among these, polyacrylamide type or polyethyleneimine type high molecular chemicals are particularly preferable. Specifically, for example, a cationic fixing agent such as Haktron KC-100 (manufactured by Hakuto Co., Ltd.) or an anionic ceramic fix ST (manufactured by Meisei Chemical Co., Ltd.) and a cationic Phyrex M (Meisei Chemical Industry Co., Ltd.) Are preferably used in combination.

  The content of the fixing agent is 0.2 to 1.0% by mass, preferably 0.2 to 0.7% by mass in terms of solid content with respect to the pulp solid content. When an anionic fixing agent and a cationic fixing agent are used in combination, the total amount is set to the above content. When the content of the fixing agent exceeds 1.0% by mass, the fixability of the heat-expandable particles is improved, but even if the heat-expandable particles are expanded, between the pulp fibers and between the heat-expandable particles and the pulp fibers. Sufficient voids cannot be ensured between them, which impairs the liquid absorbability (drug impregnation) of the drug.

  Moreover, even if the content of the heat-expandable particles is 2 to 20% by mass, delamination may easily occur from the cross section or corner of the impregnating base paper during the cutting process depending on the processing method. Therefore, in order to improve the interlaminar strength of the impregnating base paper according to the present invention, the raw pulp may contain a hot-melt fiber. In addition, content of a heat-meltable fiber is 1-10 mass% in conversion of solid content with respect to pulp solid content, Preferably it is 3-8 mass%. When the content of the heat-meltable fiber is less than 1% by mass, the effect of improving the interlayer strength due to the inclusion of the heat-foamable particles cannot be obtained. There is little improvement effect of delamination. On the other hand, even if the content of the hot-melt fiber is more than 10% by mass, the effect of improving the interlaminar strength reaches a peak and only the production cost increases. Furthermore, when the content of the hot-melt fiber exceeds 10% by mass, the liquid absorbability (impregnating property of the drug) of the base paper for impregnation tends to be lowered, and the achievement of the original object of the present invention is hindered. .

  As the heat-meltable fiber, polyethylene terephthalate (PET) fiber, polyethylene (PE) fiber, polyvinyl alcohol (PVA) fiber, EVA vinylon fiber, polyester fiber, aramid fiber, carbon fiber, rayon fiber, Acrylic fibers, polyamide fibers, glass fibers and the like are known. In the base paper for impregnation according to the present invention, the adhesiveness with the heat-expandable particles, the adhesiveness with the pulp fiber, the paper can be mixed with the pulp fiber as a raw material, and it is melted appropriately in the drying process of the paper machine, From the viewpoint of adhering to particles and pulp fibers, polyethylene terephthalate (PET) fibers, vinylon fibers, polyethylene (PE) fibers, EVA vinylon fibers and the like can be suitably used, and among these, in particular Polyethylene terephthalate (PET) fibers are preferred because they are excellent in improving the interlayer strength.

  Moreover, as for a heat-meltable fiber, that whose melt temperature of the fiber surface is 90-130 degreeC is preferable. Specifically, Sophit N720 / Kuraray, TJ04CN / Teijin, Vinylon Binder SML / Unitika, EA-CHOP / Chisso, Ester 4080 / Unitika, NBF / Daiwabo and the like can be suitably used.

The base paper for impregnation according to the present invention contains 80 to 100% by weight of softwood kraft pulp as described above, and the Canadian standard freeness (CSF) of the raw pulp when the base paper for impregnation is disaggregated is 600 to 760 ml. By adjusting and adding 2 to 20% by mass of thermally foamable particles, the density is adjusted to be 0.31 to 0.55 g / cm ³ , preferably 0.33 to 0.47 g / cm ^3. Is preferred. In this way, unlike conventional paper which is made to contain low-density by simply containing heat-expandable particles in the raw material pulp and expanding it, with expansion of the heat-expandable particles, between the pulp fibers and the heat-expandable particles A gap is formed between the pulp fibers and the gap exhibits excellent drug absorbability (drug impregnation).

  In addition, for example, using raw pulp mixed with a large amount of hardwood pulp with a short fiber length and flexible fibers, and containing heat-expandable particles in this raw pulp, adjusted to a predetermined density However, since the voids desired by the present invention cannot be obtained, the impregnation property desired by the present invention cannot be obtained.

Further, the basis weight of the base paper for impregnation according to the present invention varies depending on the use application, the amount of impregnation of the chemical agent, etc., but is 300 g / m ² or more, preferably 300 to 500 g / m ² , more preferably 350 to 450 g / m. Adjust to be in the range of ² . The paper thickness of the base paper for impregnation according to the present invention is adjusted to 700 to 1400 μm, preferably 800 to 1000 μm, depending on the intended use. Thus, the basis weight of the base paper for impregnation according to the present invention is set to 300 g / m ² or more and the paper thickness is set to 700 to 1400 μm, so that the impregnation property of the medicine is improved, and a predetermined amount of medicine is impregnated with the medicine It can be absorbed within a certain time of the process.

If the basis weight of the impregnating base paper is less than 300 g / m ² , it is difficult to impregnate a predetermined amount of the drug even if the impregnating base paper is configured as described above. On the other hand, if the basis weight of the base paper for impregnation is larger than 500 g / m ² , the amount of impregnation of the chemical increases, but only the production cost of the base paper for impregnation increases.

  The base paper for impregnation according to the present invention formed as described above uses the kit 6 solution as a test solution, and the JAPAN TAPPI No. The liquid absorption measured in accordance with “Paper—Absorptivity Test Method—Part 2: Dropping Method” described in 32-2 is 1 to 16 seconds, preferably 1 10 seconds, more preferably 1-6 seconds. The kit 6 solution refers to JAPAN TAPPI No. No. 41, castor oil: toluene: heptane = 2: 1: 1 kit number 6 test solution. Moreover, the liquid absorbency when using light oil No. 1 as a test liquid is 0 to 5 seconds, preferably 0 to 3 seconds.

  If the liquid absorption by the kit 6 liquid exceeds 16 seconds, or if the liquid absorption by light oil No. 1 exceeds 5 seconds, the impregnation of the chemical will be inferior. Cannot be impregnated.

  Moreover, the Klem water absorption measured based on JIS P 8141 is 90 to 150 mm, preferably 100 to 150 mm. If the Krem absorbency is less than 90 mm, the impregnation property of the drug is inferior, and therefore it is impossible to impregnate a predetermined amount of the drug when impregnating the drug with a gravure printing machine or the like.

  The paper making method of the base paper for impregnation according to the present invention is not particularly limited, and any of acid paper making method, neutral paper making method and alkaline paper making method may be used. However, in order to fix the heat-expandable particles with a fixing agent and to exhibit the impregnation property of the chemical, it is preferable to produce the paper with neutral papermaking so that the hot water extraction PH is 5 to 9.0. This is because the fixing agent for heat-expandable particles tends to effectively function in a neutral region.

  Also, since the paper machine is not particularly limited, for example, various known paper machines such as a long net paper machine, a twin wire paper machine, a circular net paper machine, and a short net combination machine can be used. it can.

  As described above, the case where the paper layer is composed of three layers of the surface layer, the intermediate layer, and the back layer has been described for the base paper for impregnation, but the present invention is not limited to such base paper for impregnation, and the number of intermediate layers is increased. It may be a base paper for impregnation consisting of four layers, five layers, etc., or a base paper for impregnation consisting of two paper layers, a front layer and a back layer.

  In order to confirm the effect of the base paper for impregnation according to the present invention, the following various samples were prepared, and a test for evaluating the quality of each sample was performed. In addition, in a present Example, the numerical value which shows a mixing | blending, a density | concentration, etc. is a numerical value of the solid content or the mass reference | standard of an active ingredient. Moreover, since the pulp, chemical | medical agent, etc. which are shown in a present Example are only examples, it cannot be overemphasized that this invention is not restrict | limited by these Examples, and can be selected suitably.

For comparison with 19 types of impregnating base papers (referred to as “Example 1” to “Example 19”) according to the present invention and these Examples 1 to 19, four types of impregnating papers are used. Base papers (referred to as “Comparative Example 1” to “Comparative Example 4”) were prepared in the configuration shown in Table 1.
Further, as Reference Example 1, a cushion paper used for general substrate hot pressing was evaluated.

Example 1
Blend 95% by weight of softwood bleached kraft pulp (NBKP) and 5% by weight of hardwood bleached kraft pulp (LBKP), and adjust the raw pulp to a disaggregation Canadian standard freeness (CSF) of 700 ml. A sulfuric acid band is added to the raw material pulp in an amount of 5% by mass based on the solid content of the raw material pulp, and the heat-expandable particles in the raw material pulp are added to the heat-expandable particles in the paper (trade name: Matsumoto Microsphere). F-46, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) is added so that the content becomes 4% by mass. Thereafter, the pH of the raw pulp was adjusted to 7.0, and as a fixing agent for thermally foamable particles, Hakutron KC-100 (manufactured by Hakuto Co., Ltd.) was added as an active ingredient in an amount of 0.08% by mass relative to the raw pulp solid content. Thus, a raw material slurry was prepared.

These raw material slurries are used as raw materials for the surface layer, the intermediate layer, and the back layer, and the paper layers of the surface layer, the intermediate layer, and the back layer are made by a circular three-layer paper machine, and the basis weight is 400 g / m ^2. A three-layer paper sheet for impregnation (Example 1) was obtained.

(Examples 2 to 4)
The base paper for impregnation obtained in the same manner as in Example 1 except that the blending ratio of NBKP and LBKP of the raw material pulp was changed as shown in Table 1.

(Examples 5 to 9)
Except for the fact that the freeness of the raw material pulp was changed as shown in Table 1, the base paper for impregnation obtained in the same manner as in Example 1 was used.

(Examples 10 to 14)
Except for the fact that the content of the thermally foamable particles was changed as shown in Table 1, the base paper for impregnation obtained in the same manner as in Example 1.

(Examples 15 to 19)
The contents of the heat-expandable particles were as shown in Table 1, and the other points were obtained in the same manner as in Example 1 except that the hot-melt fiber was added to the raw pulp as shown in Table 1. Base paper for impregnation.

(Comparative Example 1)
The base paper for impregnation obtained in the same manner as in Example 1 except that the blending ratio of NBKP and LBKP of the raw material pulp was changed as shown in Table 1.

(Comparative Example 2)
Except for the fact that the freeness of the raw material pulp was changed as shown in Table 1, the base paper for impregnation obtained in the same manner as in Example 1 was used.

(Comparative Examples 3-4)
A base paper for impregnation obtained in the same manner as in Example 1 except that the content of the thermally foamable particles was changed as shown in Table 1.

(Reference Example 1)
Cushion paper used for substrate hot pressing was evaluated with the same basis weight and density as the product of the present invention.

これらの全実施例及び比較例についての品質評価、すなわち坪量、密度、吸液度、クレム吸水度、層間剥離について評価試験を行った結果は表２に示すとおりであった。なお、特に断りのない限り、これらの評価試験はＪＩＳ−Ｐ８１１１に記載の「紙、板紙及びパルプ−調湿及び試験のための標準状態」に基づき、温度２３℃±１℃、湿度５０％±２％条件下で評価試験を行った。

Table 2 shows the results of quality evaluation for all of these Examples and Comparative Examples, that is, evaluation tests on basis weight, density, liquid absorption, Klem water absorption, and delamination. Unless otherwise specified, these evaluation tests are based on “standard conditions for paper, paperboard and pulp-humidity conditioning and testing” described in JIS-P8111. Temperature 23 ° C. ± 1 ° C., humidity 50% ± An evaluation test was performed under 2% conditions.

“Basis weight (g / m ² )” in Table 2 is a value measured according to “paper and paperboard—basis weight measurement method” described in JIS-P8142.

  “Paper thickness (μm)” is a value measured according to “Paper and paperboard—Test method of thickness and density” described in JIS-P8118.

“Density (g / cm ³ )” means the basis weight measured in accordance with “Paper and paperboard—basis weight measuring method” described in JIS-P8142, and the paper thickness (μm) measured by the above measuring method. It is a value calculated from

  “Liquid absorbency (seconds)” refers to JAPAN TAPPI No. It is an average value measured in accordance with “Paper—Absorptivity Test Method—Part 2: Dropping Method” described in 32-2. The test solution was dropped by 50 μl. As test solutions, (1) JAPAN TAPPI No. 41, “Kit No. 6” (castor oil: toluene: heptane = 2: 1: 1) described in “Paper and Paperboard—Hatsu Oil Level Test Method—Kit Method” and (2) stipulated in JIS-K2204 Two types of “Diesel No. 1” were used.

  “Clem water absorption (mm)” is a value in the longitudinal direction of the base paper for impregnation measured according to “paper and paperboard—water absorption test method—Klem method” described in JIS-P8141. The water used for the evaluation was distilled water adjusted to 23 ° C. ± 1 ° C.

Further, “delamination” is an evaluation of whether or not the surface layer and the intermediate layer are peeled off, and each sample is cut into a 20 cm square with a push-type paper cutter, and the four sides of the cut surface are between the surface layer and the intermediate layer. The presence or absence of peeling was observed and evaluated. The evaluation criteria were the following three levels.
(Evaluation criteria)
A: There is no peeling between the surface layer and the intermediate layer. O: There is no problem although a slight floating is observed between the surface layer and the intermediate layer. X: There is a peeling between the surface layer and the intermediate layer, which is a problem as a product.

表２に示すように、本発明に係る含浸用原紙、すなわち実施例１〜実施例１９に係る含浸用原紙であると品質評価に優れる、すなわち薬剤の含浸性及びカット適性が向上するとともに、相反する性質である薬剤の含浸性及びカット適性のバランスを良好なものとすることができることが分かる。

As shown in Table 2, the base paper for impregnation according to the present invention, that is, the base paper for impregnation according to Examples 1 to 19, is excellent in quality evaluation, that is, the impregnation property and cut suitability of the drug are improved, and the conflict It can be seen that the balance between the impregnation property and the cut suitability of the drug, which is a property to be improved, can be made favorable.

Claims (3)

A base paper for impregnation comprising at least two or more layers,
80-100 mass% of softwood kraft pulp is blended in the total raw pulp,
Containing 2 to 20% by mass of thermally foamable particles in terms of solid content with respect to pulp solid content in the total raw material pulp,
Further, an impregnating base paper having a paper thickness of 700 to 1400 μm. 2. The impregnation according to claim 1, wherein the impregnating base paper is adjusted to 600 to 760 ml in freeness of pulp fibers disaggregated according to JIS P-8220 (according to JIS-P8121). Base paper. JAPAN TAPPI No. In accordance with “Paper—Absorptivity Test Method—Part 2: Dropping Method” described in 32-2, JAPAN TAPPI No. The base paper for impregnation according to claim 1 or 2, wherein the liquid absorption measured using the test solution of kit number 6 according to 41 is 1 to 16 seconds.