JPS58167667A - Preparation of pressure-sensitive adhesive tape - Google Patents

Abstract

PURPOSE:To obtain the titled tape, by incorporating a polymer with a low content of acidic groups with a polymer having a high content of the acidic groups, neutralizing the resultant mixture in the presence of a medium in the polymerization, and applying the resultant aqueous dispersion with a high solid content to a substrate. CONSTITUTION:(A) 100 pts.wt. first polymer consisting of (i) 90-100wt% main monomer consisting essentially of an acrylic or methacrylic ester and (ii) 0- 10wt% copolymerizable unsaturated monomer having acidic groups, and having 5X10<4>-2X10<6> molecular weight with (B) 2-100pts.wt. second polymer, consisting of 60-90wt% component (i) and 10-40wt% component (ii), and having 2X10<3>-1X10<6> molecular weight, and the resultant mixture is then neutralized with an alkali and water in the absence of a medium in the polymerization to form an aqueous dispersion of 10-70wt% solid content, which is then applied onto a substrate to give the aimed tape. EFFECT:The adhesive property can be adjusted optionally according to the use.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an acrylic pressure sensitive adhesive tape.

Traditionally, this type of tape has been manufactured by applying a solution of an acrylic polymer in an organic solvent to the tape support and drying it, but this method requires a large amount of organic solvent and requires a large amount of petroleum resources. Various alternative methods have been proposed from the viewpoint of problems and pollution prevention. For example, methods are known that use so-called high-solid adhesives, which are organic solvent solutions with as little amount of solvent as possible, and methods that use hot-melt adhesives or emulsion adhesives that do not require organic solvents. .

However, high-solid adhesives have extremely high viscosity and have the disadvantage of not being able to be coated to a uniform thickness without using high-precision coating equipment, so they are hardly ever put into practical use industrially. is the actual situation. In addition, hot-melt adhesives that have a high viscosity when melted by heating are difficult to coat with a uniform thickness, while those that have a low viscosity generally have poor heat resistance and poor coating workability. There are problems such as difficulty in achieving both heat resistance and heat resistance.

On the other hand, emulsion-type adhesives have fewer problems such as those mentioned above, and whether they can provide relatively good coating workability without particularly adversely affecting heat resistance or on the other hand, the water resistance and adhesive properties of the coating film. I feel sorry for the lack of this. In other words, this type of adhesive uses an emulsion of an acrylic polymer obtained by emulsion polymerization of acrylic yarn as an adhesive, but in this case, the adhesive used during polymerization is Emulsifiers used when blending additives such as coating resins are mixed into the coating film in large amounts, usually 3 to 10% by weight, which significantly impairs the water resistance of the coating film and also has a negative effect on adhesive properties. This results in a In addition, non-emulsified emulsions also exist, but adhesives using these are not much different in characteristics from those produced by emulsion polymerization using an emulsifier, and have insufficient adhesive properties and water resistance.

In light of the above situation, the inventors have conducted intensive research and have synthesized a specific acrylic copolymer that has an acidic group introduced into the molecule using an arbitrary polymerization method and is sticky at room temperature. This is neutralized by adding alkali and water in a state containing almost no organic solvent, and is stably emulsified and dispersed in water. This is applied onto a tape support and dried to make a pressure-sensitive adhesive tape. I suggested it earlier.

The adhesive tape obtained by this method has relatively better coating properties compared to high-solid adhesives and hot-melt adhesives, and because it does not use an emulsifier, it is better than conventional emulsion adhesives. It has been found that much improved water resistance and adhesion properties can be obtained compared to .

This invention was clarified through further studies based on the basic idea of the above proposed method, and expands the scope of application of copolymers that can be used as adhesive components without impairing the excellent features of the above proposed method. The present invention also relates to a method for producing a pressure-sensitive adhesive tape, the purpose of which is to easily adjust adhesive properties. That is, the gist of the present invention is to obtain a chymotmer 9 based on acrylic ester or methacrylic ester.
0 to 100% by weight and 0 to 10% by weight of a copolymerizable unsaturated monomer having an acidic group, and has a weight average molecular weight of 5
10' to 2 x 10' of the first polymer component 10
It is composed of 60 to 90% by weight of the above-mentioned Kymotsumer and 10 to 40% by weight of the above-mentioned copolymerizable unsaturated monomer based on 0 parts by weight, and has a weight average molecular weight of 2 x 10''. and the above first and second
By neutralizing some or all of the acidic groups in the polymer molecules and dispersing these polymers, the solid content concentration is 10 to 7.
The present invention provides a method for producing a pressure-sensitive adhesive tape, which comprises preparing a 0% by weight aqueous dispersion and applying the dispersion onto a tape support.

In other words, the method of the present invention can also be used as an adhesive component for acrylic polymers, which could not be made into an aqueous dispersion that could be coated on a tape support using the previously proposed method because there are no or few acidic groups in the molecule. In addition, the adhesive properties of the adhesive tape can be arbitrarily adjusted depending on the application. Two types of polymer components, a polymer and a second polymer with many acidic groups, are mixed, and this is made in a state in which it is substantially free of medium components such as organic solvents and water during polymerization, so that it has a viscosity suitable for coating. and an aqueous dispersion with a high solid content concentration,
This is used as a pressure sensitive adhesive component.

The first polymer component is the main polymer of the adhesive component, and contains 90 to 100% by weight of a main monomer mainly composed of acrylic ester or methacrylic ester and 0 to 10% by weight of a copolymerizable unsaturated monomer having an acidic group. % by weight, with a weight average molecular weight of 5 x 10' to 2 x 1
It is in the range of 0'. If the above molecular weight is smaller than 5 x 10', the cohesive force will be insufficient when used as an adhesive tape, and even if a large amount of crosslinking agent is used to solve this problem, the balance between the various properties of the adhesive tape will be lost. . Also 2X
If it exceeds 10', water dispersion becomes difficult even when used in combination with the second polymer.

On the other hand, the second polymer component used in combination to water-disperse the first polymer component contains 10 to 40% by weight, preferably 15% by weight, of copolymerizable unsaturated polymers having acidic groups in the copolymerization components. If the unsaturated monomer content is less than 103i%, water dispersion will be difficult, and if it exceeds 40% by weight, the adhesive properties as an adhesive component will be poor. The weight average molecular weight of this second polymer is in the range of 2 x 103 to 1 x 106, and may be selected within the above range depending on adhesive properties, water dispersibility and affinity with the first polymer component.

The appropriate mixing ratio of the first polymer component and the second polymer component varies depending on the desired adhesive properties of the adhesive tape, but from the viewpoint of difficulty in water dispersion, the first polymer component should be 100 parts by weight. On the other hand, the second polymer component is 2 to 1
00 parts by weight, preferably from 5 to 80 parts by weight, which was determined based on the water dispersion index (Q) based on the polymer composition shown below.

Here, the water dispersion index (Q) is expressed by the following formula.

Q=m
As is well known, the above solubility parameter (δ) is P, A
,J,Small(J,Appl,Chem,
3-71.

(1953) proposed by the following equation.

Here, δ is the solubility parameter ([cal!/c+f]
1/2), d is the density at 25°C (ti/c-J)
, G is the Molken establishment number at 25°C, and M is the molecular weight per repeating unit (g/mol).

For example, in the homopolymer of methyl methacrylate, the basic structure is ~CH2-C(CH3) (COOCH3)-
〜, Number of constituent groups G −CH2−1133 −CHa 2 214
Therefore, ΣG=133+214X2+310-93
=778, and d=1.18, M=100
Therefore, δpMMA-118×778/1oo-92.

In addition, in the case of nitrile rubber (acrylonitrile 30 mol%), the basic structure is as follows, in the butadiene moiety, the number of constituent groups is G -CH2-2133 -CH,, = 2 111, and in the acrylonitrile moiety, the constituent groups Since the number G -CH2-1133 -CH-128 sauce CN l 410, Σ
G (butadiene) = (133 + 111) X2 = 488,
ΣG (acrylonitrile) = 133 ±28 +41
0 = 571, and d = o, 9 of this rubber
6. Since M=535, δHBH=((488X7
)+(571XMarchXO,961535=9.2).

Therefore, in this invention, when the water dispersion index of the first polymer component is Ql and that of the second polymer component is 92, 0≦91≦15.15<Q2 (in the range of 500, and When the number of parts by weight of the second polymer component with respect to the first polymer component 100] i parts is set as (100)
When the average water dispersion index (QT) expressed by xQt+nxQ2)/(100n) is in the range of 6≦QT<55, it is considered to be a water-dispersed composition with a high solid content that is extremely stable and has excellent adhesive properties. be able to.

Note that Ql and Q2 depend on the mechanical stability, storage stability, and viscosity of the aqueous dispersion, as well as the desired adhesive tape composition. In addition to disrupting the balance, there are also problems with workability, such as poor water resistance and a drop in the solution base. In addition, if Q2≦15, water dispersion as a whole becomes difficult, and Q2≦15 becomes difficult.
2 > 500, the compatibility between the first and second polymer components tends to deteriorate, and the water resistance of the pressure-sensitive adhesive composition also deteriorates. On the other hand, if QT<6, water dispersion becomes difficult, and even if water dispersion is possible, the stability is poor, making it unsuitable as an adhesive composition. Conversely, when QT > 55, water dispersion is easy, but the adhesive tape using the resulting pressure-sensitive adhesive composition will have insufficient water resistance, initial adhesion, and cold resistance, and furthermore, the low molecular weight will cause aggregation. less powerful,
If a large amount of crosslinking agent is used to prevent this, it becomes difficult to obtain a balance between various adhesive properties and stability during manufacturing.

Therefore, it is necessary to set the water dispersion index within the above range, and the mixing ratio of the first and second polymer components that satisfies this is within the range described above.

In this invention, the polymerization methods for preparing the first and second polymer components include bulk polymerization method, solution polymerization method,
Any known polymerization method such as pearl polymerization method can be employed, but among these, bulk polymerization method and solution polymerization method are particularly suitable. In this invention, the first and second polymer r components are mixed and at the time of adding the alkali and water, the medium components used in the polymerization are substantially freed. If both components are obtained by bulk polymerization, they may be mixed as they are. However, if one or both are obtained by other polymerization methods, the organic solvent, water, and other medium components used in the polymerization may be removed by appropriate means before or after mixing the first and second polymer components. need to be removed. For example, when removing the organic solvent before mixing, in the solution polymerization method, the organic solvent may be removed by means such as distillation, and in the pearl polymerization method, water may be removed by taking the particulate polymer. In addition to mixing the first and second polymer components together in a solid state using a mixing roll or a Banbury mixer, it is also possible to mix them in the presence of a small amount of an organic solvent and remove this solvent after mixing. Often, one polymer component obtained by polymerization in advance is polymerized while being dissolved in the other system to be polymerized.
and a second polymer component may be obtained.

Furthermore, when the first and second polymer components are solid before mixing, alkali and water may be added at the same time as mixing. Although it is desirable to completely remove these organic solvents, water, and other media before adding the alkali and water, there is no problem even if a small amount remains.

The weight average carbon number of the alkyl group is 2 to 15 as the chymotmer for synthesizing the first and second polymer components.
It consists of a main monomer mainly composed of (meth)acrylic acid alkyl ester and an unsaturated monomer having an acidic group in the molecule.The weight average carbon number of the alkyl group of (meth)acrylic acid alkyl ester is less than 2. When the acrylic copolymer becomes hard, the initial adhesion is poor, and when it exceeds 14, the adhesive feeling decreases and is not suitable.Preferably, the weight average carbon number of the alkyl group is 3 to 8. Good.

In addition to the above-mentioned (meth)acrylic acid alkyl ester, the main monomer may contain other monomers copolymerizable with it in a proportion of 60% by weight or less based on the total main monomer. Monomers include vinyl acetate,
Acrylonitrile, styrene, 2-methoxyethyl acrylate, vinyl ether, glycidyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)
Any of the various monomers used in the acrylic pressure-sensitive circumscription 1, such as acrylamide, can be used.

Examples of unsaturated monomers having an acidic group in the molecule used together with the above main monomers include acrylic acid,
Methacrylic acid, crotonic acid, itaconic acid, maleic acid,
Unsaturated carboxylic acids having a carboxyl group as an acidic group such as fumaric acid, styrene sulfonic acid, allyl sulfonic acid, sulfopropyl acrylate, 2-acryloyloxynaphthalene-2-sulfonic acid, 2-methacryloyloxynaphthalene-2-sulfonic acid, Examples of the acidic group include unsaturated sulfonic acids having a sulfonic group, such as 2-acrylamido-2-methylpropanesulfonic acid and 2-acryloyloxybenzenesulfonic acid.
It may also have other acidic groups, and one or more of these may be used.

Before emulsifying and dispersing the mixture of the first and second polymer components with an alkali and water, a xylene resin,
Various additives used in general pressure-sensitive adhesives, such as tackifying resins such as terpene phenol resin, coumaron indene resin, and styrene resin, various softeners, pigments, and crosslinking agents, are added in the usual amounts (for example, The tackifying resin can also be blended in a proportion of about 100 parts by weight or less per 100 parts by weight of the copolymer.In addition, these additives can be added to the acrylic copolymer by bulk polymerization or solution polymerization. etc., it may be mixed in the system in advance during polymerization.However, in this case, these additives and
This is limited to cases where machining does not adversely affect the polymerization reaction. By mixing these additives into the solid acrylic copolymer using the above method, good results can be obtained in terms of improving or homogenizing adhesive properties. moreover,
These additives may be blended into only one of the first and second polymer components and made uniform throughout when both polymer components are mixed. This method is not suitable for reactive additives. Recommended.

In this invention, an alkali and water are added to a substantially solid mixture of first and second polymers containing the acrylic copolymer prepared as described above as a main component and containing appropriate optional components. In addition, stirring and mixing neutralizes part or all of the acidic groups in the copolymer while producing a dispersion in which the copolymer is stably dispersed in water.

The alkali used here is preferably one that easily scatters and vines when the resulting dispersion is coated on a tape support and then heated and dried. By using such an alkali, it is possible to prevent the adverse effects of alkali contamination on the adhesive properties, and to obtain good adhesive properties. A typical example of a splashable alkali is ammonia. In addition, α-aminoethyl alcohol, ethylamine, propylamine, etc. can also be used. In addition, general alkalis such as caustic potash and caustic soda can also be used together with these alkalis in small amounts.

The amount of alkali used must be at least 1/10 equivalent relative to the acidic group contained in the acrylic copolymer, and if it is less than this, emulsification and dispersion will become difficult.

In general, the range of 1/10 to 3/2 equivalent is good; too much alkali is unfavorable in terms of adhesive properties, water resistance, and economic efficiency. The amount of water used is the amount necessary to make the solid content concentration of the aqueous dispersion 10 to 70% by weight. If this amount is too large, the solid content concentration will be low and heating drying will take a long time, making it impractical; if this amount is too small, the polymer will become a continuous phase and water dispersion will be difficult. □
The temperature during neutralization treatment is kept at a constant temperature depending on the type and properties of the acrylic copolymer, but generally it is between 40 and 40°C.
It is 90°C. Neutralization and production of a dispersion may be carried out by adding a predetermined amount of alkali and water at once and stirring and mixing, but preferably, first adding a predetermined amount of an alkali or an aqueous alkali solution and stirring and mixing thoroughly. After that, by gradually adding water and inverting the phase, water becomes a continuous phase and the copolymer particles are dispersed in it.
It is preferable to produce a /W type dispersion.

The dispersion obtained by the above method may be used as is as an acrylic pressure-sensitive adhesive, but if necessary, polyvinyl alcohol or other dispersion stability improvers or thickeners may be added. can. In addition, when the acrylic copolymer solid before being made into a dispersion liquid does not contain various additives added to general pressure-sensitive adhesives such as tackifier resin, softener, pigment, and crosslinking agent. If necessary, these additives may be added after forming the above-mentioned dispersion.

In particular, when crosslinking agents such as polyisocyanate compounds, epoxy resins, reactive phenolic resins, melamine resins, and peroxides are added in the above manner, the reaction is more uniform than when these crosslinking agents are mixed into the solid material in advance. Although it is somewhat inferior in terms of sex, it is possible to obtain rather good results in terms of pot life. Note that these crosslinking agents that are added later may be water-soluble or water-insoluble, and in the latter case, they may be added after being dissolved in an organic solvent (a small amount) or emulsified in water.Other than the crosslinking agent The same applies to the additives.

In this invention, the above-mentioned dispersion is applied to one or both sides of various tape supports such as plastic film, nonwoven fabric, woven fabric, paper, foil, and release paper, and the coating is heated and dried to remove moisture. By scattering the splashable alkali, it is possible to obtain a pressure-sensitive adhesive tape with desired water resistance and good adhesive properties.

Examples of the present invention will be described in detail below. In addition, in the following, the term 饅 means weight %. In addition, the results of measuring the polymer properties, aqueous dispersion properties, and tape properties in each example are summarized below. The stability, adhesive strength, and creep resistance shown in the table were measured by the following method.

<Stability> Examine the properties of pressure-sensitive adhesives when applied with a roll coater. Those that can be coated uniformly without any breakage of the emulsion are considered stable, and those that cause the emulsion to break and the coating becomes uneven are considered stable. It was unstable.

<Adhesive strength> Create a sample 20m wide and 150mm long, and attach it to J
l 2 to 20- to the stainless steel plate specified in 52-1528
Paste in one round trip. After 20 minutes of bonding, the film was peeled off at a tensile speed of 300 mm/min using a Schottspa tensile tester, and the peel adhesive strength at this time was measured. Note that the bonding and peeling operations were performed in an atmosphere of 20° C. and 165% RH.

Creep resistance〉 10 mm x 20 tran of pressure sensitive adhesive tape based on 50 μm thick polyester film on Bakelite plate.
They were pasted together with an area of , and a vertical load of 500 g was applied at a temperature of 40° C., and the time until they fell was measured.

(Viscosity) Measured at 25°C using a BH type viscometer.

Example 1 2-ethylhexyl acrylate 72 for the first polymer
0P, ethyl acrylate 280F, acrylic acid 20fi
', benzoyl peroxide 2.52 and thioglycolic acid 04f! The polymerization raw material consisting of was charged into a 3-bottle flask equipped with a stirrer, and after being sufficiently purged with nitrogen,
The polymerization reaction was started at an internal temperature of 55°C, and the temperature was gradually raised to 85°C over about 10 hours. During this time, a small amount of benzene was added to adjust the viscosity. Thereafter, the mixture was aged at 85°C for 2 hours to obtain an acrylic polymer solution. The weight average molecular weight (Mw) of this first polymer was 480,000.

On the other hand, 2-ethylhexyl acrylate 550 for the second polymer! i', 450 g of ethyl acrylate, 250 P of acrylic acid, 3 g of benzoyl peroxide, and 0.61 g of thioglycolic acid were polymerized in the same manner as the first polymer to obtain an acrylic polymer solution. . This second polymer had Mw = 280,000.

Benzene and unreacted monomers are removed from each of the polymerization products containing the first and second polymers by vacuum distillation to obtain a solid substance, and 1000% of the first polymer component is obtained.
P and the second polymer component 4007 were placed in a high viscosity stirrer (31), and 10% ammonia water (2007) was added thereto.
After adding 0y- and 9507 water and stirring at 68°C for 2 hours, the mixture was further stirred with a high-speed stirrer for 05 hours to obtain an aqueous dispersion with a solid content concentration of about 55%. 20 g of a water-soluble melamine-based crosslinking agent was added to this, and the mixture was coated onto a water-dispersed adhesive lume to a thickness of 50 μm, followed by heating and drying at 130° C. for 5 minutes to obtain a pressure-sensitive adhesive tape.

Example 2 Butyl acrylate 90 as a polymerization raw material for the first polymer
0 P, acrylonitrile 100! , azobisisobutyronitrile 107, and lauryl mercaptan 0.
4P, butyl acrylate 9!50P, acrylonitrile 50V, acrylic acid 150 ii! as raw materials for the second polymer. , azobisisobutyronitrile 10
1 and lauryl-like polymerization, the obtained polymerization product was dried under reduced pressure. The first polymer has Mw = 5
20,000, the second polymer had Mw = 450,000.

1000 fi' of this first polymer component and 400 grams of the second polymer component were put into a high viscosity stirrer No. 31, and 25 grams of aqueous ammonia and 1780 grams of water were added thereto in the same manner as in Example 1. 3 g of dibutyltin dilaurate was added to the resulting aqueous dispersion, and a pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 using this.

Example 3 2-ethylhexyl acrylate 5607, butyl acrylate 410g, acrylic acid 30g, lauryl mercaptan 2F! , and azobisisobutyronitrile 3y-
2002 of the polymerization raw material for the first polymer consisting of 2002 was separated, and a capacity 3I! After placing the mixture in a high viscosity stirrer and thoroughly purging with nitrogen, the remaining polymerization raw material solution was continuously added dropwise from the dripping port over a period of about 8 hours while maintaining the internal temperature at 706C, and then at 906C. Aged for 2 hours. The first polymer obtained had Mw = 190,000.

This polymerization product was then maintained at 90°C while a second polymer consisting of 2-ethylhexyl acrylate 100F, butyl acrylate 32g, acrylic acid 331, and benzyl peroxide 3.2,6& The polymerization raw material solution was continuously added dropwise over a period of about 4 hours, and then maintained at 90°C for another 2 hours to complete the polymerization. The second polymer produced had an Mw of 450,000.

The obtained mixture of the first and second polymer components was heated to 708C.
After cooling to 75g of 10% ammonia water and 700y of water
When the mixture was stirred for 6 hours, an aqueous dispersion having a solid content of about 60% was obtained. Subsequently, 22 g of a water-soluble melamine crosslinking agent was added to this dispersion, and using this, a pressure sensitive adhesive tape was obtained in the same manner as in Example 1.

Example 4 Butyl acrylate 8007, ethyl acrylate 200p
, methacrylic acid 5052. polyvinyl alcohol,
51! of polymerization raw materials for the first polymer consisting of 1 gram of azobisisobutyronitrile, 12 grams of lauryl mercaptan, and 2100 grams of water! After slowly stirring and purging with nitrogen for about 1 hour, the mixture was heated to 70°
The mixture was reacted at C for 5 hours to obtain an aqueous dispersion of particulate polymer.

Next, this granular polymer was taken and dried under reduced pressure to completely remove water. The first polymer obtained has Mw = 4
It was 30,000.

On the other hand, butyl acrylate 900 F, ethyl acrylate 1007, methacrylic acid 200 P, polyvinyl alcohol 117, azobisisobutyronyl-IJ 1F! ,
Using a second polymer polymerization raw material consisting of 1 g of lauryl mercaptan and 24,009 g of water, a polymerization reaction was carried out in the same manner as the first polymer, and the polymer was dried to obtain a granular polymer. The Mw of this second polymer was 410,000.

After mixing the first polymer component 9457 and the second polymer component 216 grams using a mixing roll, 857 grams of 10% aqueous ammonia and 420 grams of water were added.

was added and mixed, and this was further placed in a high viscosity stirrer, and 6562 water was added and stirred to obtain an aqueous dispersion. Add about 60f of 125' benzoyl peroxide to this aqueous dispersion! A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 by adding a solution of 100% dissolved in toluene and stirring uniformly.

Example 5 A first polymer raw material consisting of 8509 2-ethylhexyl acrylate, 150 P vinyl acetate, 70 g acrylic acid, 3y azobisisobutyronitrile, 10707 benzene, and 2v thioglycolic acid was prepared. 3J, and stirred for about 60 minutes in a nitrogen gas stream, and then reacted for about 7 hours at an internal temperature of 65°C.
Next, the internal temperature was raised to 85°C, and the reaction was further carried out for 2 hours to obtain an acrylic polymer solution. This first polymer is M
w = 210,000.

On the other hand, using the polymerization raw materials for the second polymer consisting of 850g of 2-ethylhexyl acrylate, 150P of vinyl acetate, 200P of acrylic acid, 3fI of azobisisobutyronitrile, 1200y-1 of benzene, and 27g of thioglycolic acid, the first Polymerization was carried out in the same manner as the polymer described above to obtain an acrylic polymer solution. This second polymer has Mw=2
It was 40,000.

After mixing 2000 fF of the first polymer solution and 1000 P of the second polymer solution, and further blending 75 g of styrene resin and uniformly dissolving and mixing, benzene was removed by vacuum distillation method to form a viscous acrylic solid. I got something. After uniformly dispersing 5% ammonia water 3701i' into this solid, 757 DOP was added, and then 2100S
' of water was added and mixed uniformly to obtain an aqueous dispersion with a solid content concentration of about 40%.

5 grams of a trifunctional polypropylene compound was added to this dispersion, and a pressure-sensitive adhesive tape was obtained in the same manner as in Example 1.

Claims (3)

[Claims] (1) Consisting of 90 to 100% by weight of a main monomer mainly composed of acrylic ester or methacrylic ester and 0 to 10% by weight of a copolymerizable unsaturated heptamer having an acidic group, with a weight average molecular weight of 5XIO' to 2X106 It consists of 60 to 90 weight percent of the above main monomer and 10 to 40 weight percent of the above copolymerizable unsaturated monomer to 100 parts by weight of the first polymer component, and has a weight average molecular weight of 2 x 103
~I X 10' second polymer component 2-100
parts by weight are mixed, and water and an alkali are added to this mixture in a state substantially free of a polymerization medium to neutralize some or all of the acidic groups in the first and second polymer molecules. A method for producing a pressure-sensitive adhesive tape, which comprises: preparing an aqueous dispersion with a solid content concentration of 10 to 70% by weight in which these polymers are dispersed; and applying this onto a tape support. (2) The first polymer component is m x δ / weight [where m is the number of parts by weight of the unsaturated monomer having an acidic group based on 100 parts by weight of the main monomer, δ is the solubility parameter of the polymer consisting of the monomer alone, Mw is the weight average molecular weight (10,000) of the acrylic copolymer, and the water dispersion index (ql) is in the range O<Ql<15, and the second polymer component has a similar water dispersion index. (Q2) is 15<Q2<5
00, and 6 ((100xQ1+n XQ2)/
(100+”)≦55 (where n is the number of parts by weight of the second polymer component relative to 100 parts by weight of the first polymer component).Production of the pressure-sensitive adhesive tape according to claim (1) Method. (3) A method for producing a pressure-sensitive adhesive tape according to claim (1) or (2), wherein the alkali is a splashable alkali such as ammonia.