JP2011206701A - Impregnant for paper-made masking tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impregnant for a paper-made masking tape which gives a paper base material that has good strength and elongation, in which deterioration of strength when wet is suppressed.SOLUTION: The impregnant for the paper-made masking tape contains an emulsion obtained by emulsion polymerization of a monomer component consisting of 65 to 99.5 mass% of (meth)acrylic acid alkyl ester, 0.1 to 15 mass% of itaconic acid and 0 to 20 mass% of unsaturated monocarboxylic acid. Paper impregnated with the impregnant for the paper-made masking tape gives the paper base material having good strength and elongation, in which deterioration of strength when wet is suppressed. Thus the paper-made masking tape having the paper base material can be produced.

Description

  The present invention relates to an impregnating agent for paper masking tape, a masking tape paper base impregnated with the impregnating agent, and a paper masking tape provided with the paper base.

  Masking tape is used by sticking to various adherends for the purpose of shielding the parts that are not painted and preventing contamination during car painting, curing at the construction site, spray painting, etc. . In general, masking tape is made of paper such as Japanese paper, crepe paper, polyester film, polypropylene film, resin film such as soft vinyl chloride film, cloth, etc., with one side of rubber adhesive, acrylic adhesive, etc. An adhesive layer is provided, and the other surface is provided with a release agent layer that imparts peelability to the adhesive. The masking tape is usually manufactured and sold in the form of a roll, and when used, a required amount is unwound from the roll tape, cut off, and attached to the adherend.

  Since the masking operation is usually a manual operation, the masking tape is required to be cut by hand. From the viewpoint of hand cutting properties, a masking tape based on paper is advantageous. However, a paper base is small in strength, has a significant decrease in strength when wet, and has a relatively small elongation. In addition, there is a problem that the followability of the masking tape to an adherend with unevenness is small. In order to improve these properties, the paper substrate is usually treated with an impregnating agent.

  Conventionally, various organic solvent-based resins and water-based resins have been used as the impregnating agent, but recently, water-based resins are increasingly used from the environmental viewpoint. Specific examples include emulsions of synthetic rubber such as SBR, MBR and NBR, natural rubber latex, acrylic resin emulsion, vinyl acetate resin emulsion, vinyl chloride resin emulsion and the like. Acrylic resin, vinyl acetate resin, and vinyl chloride resin were characterized by copolymerizing various vinyl monomers that can be copolymerized with acrylic acid ester, vinyl acetate, and vinyl chloride as the main components. Resin emulsions are also present. For example, a resin emulsion using a copolymer of N-methylol (meth) acrylamide has been proposed to improve tensile strength and water resistance (see Patent Document 1). However, since N-methylol (meth) acrylamide generates formaldehyde during the reaction, in recent years, restrictions on use and self-restraint of use tend to be strengthened. Furthermore, Patent Document 1 describes that it is effective to perform a crosslinking reaction in order to improve the tensile strength. However, since the flexibility is lost when the crosslinking reaction is performed, a balanced impregnated paper is used. There is a problem that it is difficult to obtain.

JP-A-9-279085

  It is an object of the present invention to provide a paper masking tape impregnating agent that provides a paper base material having good strength and elongation and improved strength reduction when wet, and impregnating the impregnating agent. Another object of the present invention is to provide a masking tape paper base material and a paper masking tape provided with the paper base material.

  As a result of intensive studies to solve the above problems, the present inventors combined (meth) acrylic acid alkyl ester and itaconic acid at a specific ratio, and optionally combined with an unsaturated monocarboxylic acid for emulsion polymerization. It was found that the paper masking tape impregnating agent containing the emulsion obtained above can provide a paper base material having good strength and elongation and improved strength reduction when wet. Was completed.

  That is, the present invention emulsion-polymerizes a monomer component consisting of 65 to 99.5% by weight of (meth) acrylic acid alkyl ester, 0.1 to 15% by weight of itaconic acid and 0 to 20% by weight of unsaturated monocarboxylic acid. It is related with the impregnating agent for paper masking tapes containing the emulsion obtained by this. The present invention further relates to the above-mentioned impregnating agent for paper masking tape, which contains a crosslinking agent. The present invention also relates to a paper base material for paper masking tape impregnated with any of the above paper masking tape impregnating agents, and to a paper masking tape provided with the paper base material.

  According to the paper masking tape impregnating agent of the present invention, there is provided a masking tape paper base material having good strength and elongation and improved strength reduction when wet. The paper masking tape provided with the paper base material impregnated with the paper masking tape impregnating agent of the present invention has excellent hand cutting properties and good elongation, so that it can follow an adherend with a curved surface or unevenness. Is also excellent.

  The impregnating agent for paper masking tape of the present invention is a monomer comprising 65 to 99.5% by mass of (meth) acrylic acid alkyl ester, 0.1 to 15% by mass of itaconic acid and 0 to 20% by mass of unsaturated monocarboxylic acid. It contains an emulsion obtained by emulsion polymerization of the components (the total of the monomer components is 100% by mass) in an aqueous medium.

  The alkyl group of the (meth) acrylic acid alkyl ester that is the monomer component is not particularly limited, and may be a linear, branched, or cyclic alkyl group. The alkyl group preferably has 1 to 18 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 10 carbon atoms.

  Examples of (meth) acrylic acid alkyl esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, and n-octyl. Acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, isononyl acrylate, isodecyl acrylate, n-cetyl acrylate, n-stearyl acrylate, isostearyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl Methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-he Sill methacrylate, cyclohexyl methacrylate, n- octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, isodecyl methacrylate, tridecyl methacrylate, stearyl methacrylate, and the like. A (meth) acrylic acid ester in which the alkyl group is cyclic (for example, a cyclic alkyl group having 3 to 10 carbon atoms (such as a cyclohexyl group)) can also be used, but the alkyl group is a linear or branched (meth) acrylic ester. It is preferable to use in combination with an acid ester.

The (meth) acrylic acid alkyl ester may be used alone or in combination of two or more. From the point of making a flexible paper, it is preferable to use a combination of one or more of (meth) acrylic acid alkyl esters having a linear or branched alkyl group having 1 to 10 carbon atoms. For example, n -Butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are mentioned. For the copolymer obtained by emulsion polymerization, it is preferable to select the (meth) acrylic acid alkyl ester so that the Tg estimated from the monomer component is −10 ° C. or lower. The formula for estimating the Tg of the copolymer from the monomer component is calculated from the value of the Tg of the homopolymer of each component by the following formula (for example, see Adhesive Handbook 2nd Edition (Japan Adhesive Tape Industry Association), page 144).
1 / Tg = (W ₁ / Tg ₁ ) + (W ₂ / Tg ₂ ) +... (W _n / Tg _n )
Tg represents the glass transition point (K) of the copolymer, Tgn represents the glass transition point (K) of the homopolymer of monomer n, and Wn represents the weight fraction of monomer n.

  In a total of 100% by mass of the monomer components, (meth) acrylic acid alkyl ester is 65 to 99.5% by mass, and itaconic acid is 0.1 to 15% by mass. By combining (meth) acrylic acid alkyl ester and itaconic acid and using them in the above amounts, there is an effect of greatly improving the tensile strength of the impregnated paper and the decrease in strength when wet. From the viewpoint of suppressing strength reduction when the paper substrate is wet, the alkyl (meth) acrylate is preferably 70 to 99% by mass, more preferably 80 to 95% by mass, preferably Itaconic acid is 0.5 to 15% by mass, and more preferably 1 to 10% by mass.

  In the present invention, it is preferable to use an unsaturated monocarboxylic acid as a monomer component from the viewpoint of improving strength and elongation. Specific examples include acrylic acid, methacrylic acid, β-carboxyethyl acrylate, 2-acryloyloxyethyl-succinic acid, and the like.

  Unsaturated monocarboxylic acid can be made into 20 mass% or less in 100 mass% of a total of a monomer component, and preferably is 1-10 mass% from the point of the effective improvement of intensity | strength and elongation.

  As the monomer component, monomers other than those described above can be used as long as the effects of the present invention are not impaired. For example, (meth) acrylonitrile, styrene, carboxylic acid vinyl ester, maleic acid, fumaric acid and the like can be mentioned. Moreover, what substituted the alkyl group of the (meth) acrylic-acid alkylester by the hydroxyl group, the alkoxy group, etc. can be used. One of these may be used alone, or two or more of these may be used in combination.

  An emulsion is obtained by emulsion polymerization of monomer components. The means for emulsion polymerization is not particularly limited, and known means can be used. Specifically, a method of emulsifying a monomer component with a surfactant using water as a solvent, adding a polymerization initiator, and performing a polymerization reaction at a predetermined temperature can be mentioned. The temperature and time of the polymerization reaction can be appropriately selected. The monomer component can be added in several times (for example, twice), and the polymerization may be started when a part of the monomer component is added.

  In said method, surfactant is not specifically limited, The well-known surfactant used for emulsion polymerization can be used. Surfactants may be used alone or in combination of two or more.

  The surfactant may be a non-reactive surfactant or a reactive surfactant having a radical polymerizable group in its structure.

  Non-reactive surfactants include anionic and nonionic surfactants. Examples of anionic surfactants include fatty acid salts, alkyl (allyl) sulfonates, alkyl sulfate esters, and polyoxyethylene alkyl (phenyl) ether sulfates. Nonionic surfactants include polyoxyethylene. Examples include alkyl (phenyl) ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer.

  The reactive surfactant includes anionic and nonionic surfactants. Examples of the anionic reactive surfactant include, but are not limited to, ether sulfate type reactive surfactants, sodium alkylallylsulfosuccinate, and phosphate ester type reactive surfactants.

  The ether sulfate type reactive surfactant has polyoxyalkylene alkyl ether sulfate or polyoxyalkylene phenyl ether sulfate as a basic skeleton, and has a polymerizable alkenyl group (for example, allyl group), (meth) acryloyl group, etc. Compounds having are included. For example, Latemuru PD-104, PD-105 (manufactured by Kao Corporation), Eleminol RS-30, NHS-20 (manufactured by Sanyo Chemical Industries), Aqualon KH-5, KH-10, KH-20 (Daiichi Kogyo Seiyaku) Co., Ltd.), Adeka Soap SR-10, SR-20, etc. (manufactured by ADEKA Corporation).

  The phosphate ester type reactive surfactant includes an alkyl phosphate ester, a polyoxyalkylene alkyl ether phosphate (salt) or a polyoxyalkylene phenyl ether phosphate (salt) as a basic skeleton, and a polymerizable alkenyl group ( For example, a compound having an allyl group), a (meth) acryloyl group or the like is included. For example, SIPOMER PZ-100 (manufactured by Rhodia Nikka Co., Ltd.), H-3330PL, New Frontier S-510 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Maxemul 6106, 6112 (manufactured by Unikema), Adekaria soap PP-70 (stocks) Company ADEKA).

  Examples of other anionic reactive surfactants include SIPOMER COPS1 (manufactured by Rhodia Nikka Co., Ltd.), Eleminol JS-20 (manufactured by Sanyo Kasei Kogyo Co., Ltd.), Maxemul 5010, 5011 (manufactured by Unikema).

  On the other hand, the nonionic reactive surfactant includes a compound having a polyoxyalkylene alkyl ether as a basic skeleton and a polymerizable alkenyl group (for example, allyl group), (meth) acryloyl group, and the like. For example, ADEKA rear soap NE-10, NE-20, NE-30, ER-10, ER-20, ER-30 (manufactured by ADEKA Co., Ltd.), Latemul PD-420, PD-430, PD-450 (Co., Ltd.) Kao), Aqualon RN-10, RN-20, RN-30, RN-50 (Daiichi Kogyo Seiyaku Co., Ltd.).

  In general, as a surfactant for emulsion polymerization of an acrylate ester, polyoxyethylene alkyl (phenyl) ether sulfate and polyoxyethylene alkyl (phenyl) ether which are non-reactive surfactants are used alone or in combination. Although it is used, it is preferable to combine with a reactive surfactant in order to reduce adverse effects on the adhesive properties when manufacturing an adhesive product, and more preferably, polymerization is performed using only the reactive surfactant. It is preferable to perform the polymerization, and it is particularly preferable to perform the polymerization using an ether sulfate type reactive surfactant.

  As for the usage-amount of surfactant, 0.5-10 mass parts is preferable with respect to 100 mass parts of monomer component whole quantity, More preferably, it is 1-5 mass parts.

  The polymerization initiator is not particularly limited, and a known polymerization initiator used for emulsion polymerization can be used. One polymerization initiator may be used alone, or two or more polymerization initiators may be used in combination.

  Polymerization initiators include persulfate initiators such as sodium persulfate, potassium persulfate, and ammonium persulfate, organic peroxide initiators such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, Redox initiators using a combination of a hydrogen oxide initiator and tartaric acid, azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 4,4′-azobis-4-cyanoyoshi Examples thereof include azo initiators such as herbic acid. The azo initiator includes a water-soluble azo initiator such as 2,2'-azobis (2-amidinopropane) dihydrochloride.

  The amount of the polymerization initiator used is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the total monomer components.

In the polymerization reaction, a chain transfer agent, a neutralizing agent, a protective colloid, and the like can be used as necessary.

  The emulsion obtained by the polymerization reaction can have a solid content concentration of 35 to 60% by mass, an average particle size of 0.08 to 0.8 μm, and a viscosity of 10 to 10,000 mPa · s (25 ° C.). It can be. The average particle diameter is the median diameter measured with a laser diffraction / scattering particle size distribution analyzer, and the viscosity is the value measured with a B-type viscometer.

  In the present invention, the emulsion can be used as an impregnating agent as it is, but from the viewpoint of workability and throughput, the concentration can be reduced to 35% by mass or less by dilution. The viscosity is preferably 20 seconds or less (# 3 Zahn cup, room temperature), more preferably 13 seconds or less (# 3 Zahn cup, room temperature).

  In the present invention, a crosslinking agent, an antifoaming agent, a filler, a wetting agent, a preservative, a film-forming aid, a dye, a pigment, and the like are added to the emulsion and optionally diluted to obtain an impregnating agent. can do. In particular, it is advantageous to add a crosslinking agent from the viewpoint of improving the strength.

  Examples of the crosslinking agent include carbodiimide compounds, epoxy compounds, oxazoline compounds, isocyanate compounds, aziridine compounds, metal complexes, and the like.

The carbodiimide compound is not particularly limited as long as it is a compound having a carbodiimide bond (—N═C═N—) in the molecule. Examples of the carbodiimide compound include carbodilite E-01, E-02, V-02, V-04, and V-06 (manufactured by Nisshinbo Chemical Co., Ltd.).
The epoxy compound is not particularly limited as long as it is a compound containing two or more epoxy groups. For example, Denacol EX series (manufactured by Nagase ChemteX Corporation), SR series (manufactured by Sakamoto Pharmaceutical Co., Ltd.) and the like can be used.
The oxazoline compound includes a polymer containing an oxazoline group. For example, Epocros WS-500, 700, K-1010E, K-2010E, K-3010E, K-1020E, K-1030E (manufactured by Nippon Shokubai Co., Ltd.) and the like can be used.
The isocyanate compound is not particularly limited as long as it is a compound containing two or more isocyanate groups. For example, Duranate WB40, WT20, WT30, WT50 (manufactured by Asahi Kasei Chemicals Corporation) can be used.
Examples of the metal complex include organic titanium compounds, and titanium chelate compounds are preferable. For example, Olga Chicks TC-400, 300, 310, 315 (Matsumoto Kosho Co., Ltd.) can be used.

  The amount of the crosslinking agent used can be 15 parts by mass or less, preferably 0.05 to 10 parts by mass, more preferably 0.1 to 100 parts by mass with respect to a total of 100 parts by mass of the monomer components. 5 parts by mass.

  The paper base material for masking tape can be impregnated with the impregnating agent of the present invention. The impregnation treatment is performed by immersing the paper substrate in the impregnating agent.

According to the impregnating agent of the present invention, the coating amount (impregnation amount) on a paper substrate having a basis weight of about 30 g is 3 to 30 g / m ² by dry weight, and the strength and elongation are improved, and the strength is reduced when wet. Can be suppressed. The coating amount (impregnation amount) is preferably 5 to 20 g / m ² , and more preferably 7 to 15 g / m ² .

  The paper substrate is not particularly limited, but among them, Japanese paper is preferable. Here, Japanese paper means paper obtained by mechanical papermaking by a method of pouring. Washi base paper is preferably made of kraft pulp as the main raw material, but in addition to kraft pulp, for improving mechanical strength and water resistance, for example, polyester fiber, vinylon fiber, manila hemp and other paper-making fibers are used. You may use together. In some cases, the impregnation treatment may be performed at the paper making stage.

  On one side (back side) of the impregnated paper substrate, a coating layer of the back surface treatment agent may be provided. Back treatment agent is not particularly limited, natural products such as shellac, polyvinyl alcohol resin, polyvinyl acetate resin, vinyl acetate-acrylate copolymer resin, hydroxyl group-containing aliphatic unsaturated hydrocarbon- (meth) acrylonitrile copolymer Examples thereof include one or more selected from the group consisting of a resin, hydroxy (meth) acrylate, (meth) acrylonitrile, and (meth) acrylic acid, and a copolymer resin of (meth) acrylic acid ester and styrene. The thickness of the back surface treatment agent is usually 0.1 to 20 μm, preferably 1 to 10 μm in terms of dry film thickness.

A release agent can also be applied on the back surface treatment agent in order to smoothly release (develop) the masking tape wound in a roll. The release agent is not particularly limited. The coating amount of the release agent is usually 0.01 to 10 g / m ^2, preferably from 0.1 to 1 g / m ^2.

  An adhesive layer can be provided on the opposite surface (front surface) of the impregnated paper substrate. The pressure-sensitive adhesive is not particularly limited, and examples thereof include natural rubber-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, and acrylic pressure-sensitive adhesives. In the pressure-sensitive adhesive, pigments, dyes, ultraviolet absorbers, fillers, anti-aging agents, softeners, and the like can be blended. The thickness of the pressure-sensitive adhesive is usually 5 to 100 μm, preferably 10 to 30 μm.

  The masking tape of the present invention can be suitably used not only as a coating masking tape but also as a so-called paper adhesive tape for packaging, for example.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited only to these examples. The parts are expressed in parts by mass.

Example 1
Preparation of impregnating agent: 200 parts of distilled water, ether sulfate type reactive surfactant (Aqualon KH-10: Daiichi Kogyo Seiyaku Co., Ltd.) 0.45 parts, 2-ethylhexyl acrylate (2-EHA) (ie 23.55 parts), n-butyl acrylate (n-BA) (ie 3.0 parts), methyl methacrylate (MMA) (ie 3.0 parts), itaconic acid (ITA) (ie 0.45 parts), heated to 80 ° C. under a nitrogen stream, and then persulfuric acid A solution prepared by dissolving 0.6 part of potassium in 10 parts of distilled water was dropped, and after 10 minutes, the remaining 2-EHA (ie, 211.95 parts), n-BA (ie, 27.0 parts), MMA (Snow 27.0 parts), ITA (that is, 4.05 parts), an ether sulfate type reactive surfactant (Aqualon KH-10: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 4.05 parts, distilled The monomer emulsion emulsified and dispersed in 90 parts of water was continuously added in 2 hours, and the reaction was further continued at 80 ° C. for 2 hours to complete the polymerization, followed by cooling. After adjusting the pH to 7.5 with aqueous ammonia, the mixture was filtered through a wire mesh or the like to obtain an emulsion having a solid content of 50% (viscosity 3000 mPa · s (25 ° C.), average particle diameter of emulsion 0.1 μm).

Treatment of paper substrate with impregnating agent A paper substrate was prepared by impregnating the impregnating agent of Example 1 into Japanese paper (basis weight: 31 g / m ² ) composed of wood pulp and a small amount of vinylon by dipping. About 10 g / m ² ). The following evaluation was performed about the obtained paper base material and Japanese paper (comparative example 1) before a process.
(1) Tensile strength: Measurement was performed according to JISZ0237 using a paper base material having a width of 15 mm as a sample.
(2) Tensile strength after immersion in water: Based on the general method (immersion) of JISP8135, the tensile strength was measured after immersion.
(3) Elongation: Measurement was performed according to JISZ0237 using a paper base material having a width of 15 mm as a sample.
The results are shown in Table 1.

Preparation of impregnating agents of Examples 2 to 4 and Comparative Example 2 Except for changing the composition of the monomer component to the composition of Table 1, the impregnating agent was prepared and the paper substrate was treated in the same manner as in Example 1. Then, each physical property was measured. The results are shown in Table 1.

  It can be seen that the paper substrate of the example treated with the impregnating agent of the present invention has good strength and elongation and improved strength reduction when wet. As shown in Comparative Example 2, when itaconic acid was absent, the effect of improving strength and elongation was small, and the improvement in strength reduction when wet was also small.

Preparation of Impregnating Agents of Examples 5 to 11 and Comparative Examples 3 to 5 Impregnating agents were prepared in the same manner as in Example 1 except that the composition of the monomer component was changed to the composition shown in Table 2. Acrylic acid was added in two portions in the same manner as the other monomers (first time: 1/10 of the amount in Table 2. Second time: remainder). After treating the paper substrate with the impregnating agent, each physical property was measured in the same manner as in Example 1. The results are shown in Table 2.

  From Table 2, it can be seen that the strength and elongation of the paper base material treated with the impregnating agent of the example using acrylic acid was further improved. However, as shown in Comparative Examples 3 to 5, the improvement effect was small unless it was used in combination with itaconic acid. In particular, it can be seen that when used in combination with itaconic acid, the effect of suppressing the decrease in strength after water wetting is high.

Preparation of impregnating agents in Examples 12 to 20 The composition of the monomer component was changed to the composition shown in Table 3, and after obtaining an emulsion, the same procedure as in Example 1 was carried out except that the crosslinking agent was blended in the amount shown in Table 3. An impregnating agent was prepared. After treating the paper substrate with the impregnating agent, each physical property was measured in the same manner as in Example 1. The results are shown in Table 3.

Preparation of impregnating agents of Examples 21 to 29 The composition of the monomer component was changed to the composition of Table 4 to obtain an emulsion, and then the same as Example 1 except that 3 parts by mass of the crosslinking agent shown in Table 4 was blended. Thus, an impregnating agent was prepared. After treating the paper substrate with the impregnating agent, each physical property was measured in the same manner as in Example 1. The results are shown in Table 4.

  From Tables 3 and 4, it can be seen that the paper base treated with the impregnating agent of the example blended with the cross-linking agent is significantly improved in strength, but is not easily damaged in flexibility (elongation).

  The paper masking tape impregnating agent of the present invention is industrially useful because it provides a masking tape paper base material that has good strength and elongation and improved strength reduction when wet. The paper masking tape provided with the paper base material impregnated with the paper masking tape impregnating agent of the present invention has excellent hand cutting properties and good elongation, so that it can follow an adherend with a curved surface or unevenness. It is also excellent and convenient.

Claims (4)

  Contains an emulsion obtained by emulsion polymerization of a monomer component consisting of 65 to 99.5% by weight of (meth) acrylic acid alkyl ester, 0.1 to 15% by weight of itaconic acid and 0 to 20% by weight of unsaturated monocarboxylic acid Impregnating agent for paper masking tape.   Furthermore, the impregnating agent for paper masking tapes of Claim 1 containing a crosslinking agent.   A paper base material for a paper masking tape impregnated with the paper masking tape impregnating agent according to claim 1 or 2.   A paper masking tape comprising the paper substrate according to claim 3.