JP2934586B2 - Thermoplastic addition polymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic addition polymer and a method for producing the same, and more particularly, to a thermoplastic addition polymer having a plurality of copolymer parts extending radially from a central part and a method for producing the same. . This thermoplastic addition polymer is, for example, a star block copolymer.

[0002]

2. Description of the Related Art A thermoplastic polymer having a plurality of polymer portions radially extending from a central portion includes a condensation polymer portion and an acrylic addition polymer portion radially extending from the condensation polymer portion. (See JP-A-63-132914), a star-shaped polymer having a structure in which three polymer portions formed by polymerization centering on a diphenylethylene derivative extend radially (see JP-A-Heisei 3 JP-A-190911), a star polymer having a structure in which two or more polymer portions formed by polymerization centering on a polyfunctional crosslinking agent having at least two polymerizable double bonds and extending radially (see Table 1). JP-A-5-500827), a star block polymer produced by photoinitiated radical polymerization utilizing a dithiocarbamate group (Poly.
J., 16 , 511 (1984)), a star-shaped block polymer produced by thermal cleavage radical polymerization using a triphenylmethyl group introduced into a polymer terminal (Poly. Bull., 16 , 277).
(1985)).

[0003] In these conventional thermoplastic polymers, the combination of a plurality of polymer parts is limited, the polymer part is derived from a homopolymer, or the monomer unit constituting the polymer part is not included. There are problems such as being limited in kind or being produced by light (ultraviolet) radical polymerization which is unsuitable for industrial mass production. Further, in the conventional block polymer, blocks of the same polymer cause phase separation, so that the transparency is lowered and the mechanical strength is weak.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel thermoplastic polymer having excellent transparency and mechanical strength, which is a block polymer, which can enhance the functionality without causing phase separation. Is to provide coalescence. Another object of the present invention is to provide a production method capable of easily producing such a thermoplastic addition polymer industrially.

[0005]

According to the first aspect, the thermoplastic addition polymer of the present invention comprises a polymer aggregate having a polyvalent mercaptan portion and a plurality of copolymer portions.
And has a parallel light transmittance of 85% or more . Polyvalent mercap
The tan moiety is converted from a polyvalent mercaptan to its mercapto group.
This is the remaining portion where protons are dissociated. Copolymer portion, Ru is composed of two or more different polymerizable unsaturated monomer units. One end of each carbon atom of the copolymer portion is a polyvalent mercury.
Bonds to sulfur atoms derived from mercapto groups in the butane moiety
By, polymer has an extending VITA structure radially from polyvalent mercaptan moiety copolymer portion. Shared weight
Two or more different polymerizable unsaturated monomers composing the united portion
The composition of the body units differs from one copolymer part to another.
As a result, it continuously changes throughout the polymer aggregate .

According to a second aspect, the thermoplastic addition polymer of the present invention comprises two or more different polymerizable unsaturated monomer units, and has a number average molecular weight of 4,000 to 1,000,000. And has only one glass transition temperature peak having a width of 50 ° C. or more and a parallel light transmittance of 85% or more. According to the second aspect, the thermoplastic addition polymer of the present invention preferably has a glass transition temperature peak having a width of 80 ° C. or more.

[0007] The thermoplastic addition polymer of the present invention may further contain sulfur atoms in the range of 0.005 to 4% by weight. Method for producing a thermoplastic addition polymer of the present invention, viewed including the preparation and process the prepolymerization step and the adding step and the polymerization step, the
1. The polymerization rate of the polymerizable unsaturated monomer is 50% by weight or less.
At the start of the addition process . The preparing step is a step of preparing a mixture containing the first polymerizable unsaturated monomer and the polyvalent mercaptan. The prepolymerization step is polyvalent
First polymerizability starting from the mercapto group of mercaptan
This is a step of performing radical polymerization of an unsaturated monomer. The addition step is a step of gradually adding a second polymerizable unsaturated monomer having a composition different from that of the first polymerizable unsaturated monomer to the mixture obtained in the preparation step. Polymerization step, during the addition step, a first polymerizable unsaturated monomer and the second polymerizable unsaturated monomer as beginning a mercapto group of the polyvalent mercaptan
This is a step of performing radical polymerization of

[0008] The method for producing a thermoplastic addition polymer of the present invention, the polymerization of the first polymerizable unsaturated monomer 10-30
It is preferred to start the addition step when it is% by weight.

[0009]

[Explanation of means]

[Thermoplastic Addition Polymer] According to the first embodiment, the thermoplastic addition polymer of the present invention comprises a polymer aggregate having a polyvalent mercaptan portion and a plurality of copolymer portions. The copolymer portion extends radially from the polyvalent mercaptan portion. The copolymer portion radially extends from the polyvalent mercaptan portion means that two copolymer portions per polymer extend in two directions from the polyvalent mercaptan portion (also when the copolymer portion extends linearly). And 3 per polymer
This is the case where at least three copolymer parts extend in three or more directions from the polyvalent mercaptan part. A carbon atom at one end of the copolymer moiety is bonded to a sulfur atom derived from the mercapto group of the polyvalent mercaptan moiety.

[0010] The polyvalent mercaptan moiety refers to a remaining portion in which protons of a plurality of mercapto groups have been dissociated from a polyvalent mercaptan (a mercaptan having two or more mercapto groups). In the present invention, as the polyvalent mercaptan moiety,
Trimethylolpropane trithioglycolate, trimethylolpropane trithiopropionate, pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, dipentaerythritol hexakisthioglycolate, which is a trivalent to hexavalent mercaptan; It is preferably derived from at least one compound selected from dipentaerythritol hexakisthiopropionate. From the polyvalent mercaptan portion derived from a trivalent to hexavalent mercaptan, the copolymer portion has a star-shaped structure extending radially in three to six directions, so that the copolymer has a slightly different composition between adjacent polymers. Since the polymer portions are easily entangled and do not take a large phase separation form, the thermoplastic addition polymer can have higher parallel light transmittance.

The copolymer portion is composed of two or more different polymerizable unsaturated monomer units. The polymerizable unsaturated monomer unit is a monomer unit derived from a polymerizable unsaturated monomer mentioned in the description of the production method described later. 2
The different polymerizable unsaturated monomer units of at least one kind include a unit derived from the first polymerizable unsaturated monomer capable of forming the first polymer portion (first monomer unit) and a second polymerizable unsaturated monomer unit. And a unit derived from a second polymerizable unsaturated monomer (second monomer unit) capable of forming a second polymer portion having physical properties different from those of the first polymer portion.

Further, the copolymer portion has a composition which is continuously changed in the entire polymer aggregate constituting the thermoplastic addition polymer. This means that the copolymer portion does not consist solely of a first polymer portion and a second polymer portion for the entire assembly, but rather the composition of the first polymer portion and the second polymer portion. That is, the composition of the polymer portion has a continuous composition mixed in an arbitrary ratio. The composition of the polymerizable unsaturated monomer units is shown in an averaged form for the entire assembly.

[0013] The thermoplastic addition polymer of the present invention may be a polymer having only a copolymer portion having a monomer unit composition in the above-mentioned averaged form, or a first polymer portion and a second polymer. A copolymer having a continuous composition in which the composition of the coalesced portion is mixed at an arbitrary ratio but having different physical properties from a mixture of a copolymer having no block structure, and having a composition of the first polymer portion. It shows different physical properties from a so-called block polymer or graft polymer having a coalesced portion and a copolymer portion having the composition of the second polymer portion.

The thermoplastic addition polymer of the present invention can have various functions by having a copolymer portion having a large number of compositions, in terms of the entire polymer aggregate constituting the thermoplastic addition polymer. However, a large number of compositions are slightly different from each other as a whole, so that phase separation is hardly caused. Such a form effectively acts on the expression of a new function.

The large number of compositions means that the copolymer portion has a composition composed of continuously changing constituent monomer units as a whole. For example, in a polymer having a wide glass transition point, Having a glass transition point at the upper limit of the glass transition temperature peak from the composition of the monomer units constituting the polymer portion having the lower glass transition point of the glass transition temperature peak so as to have a continuous glass transition point. It means that it has a composition up to the composition of the monomer units constituting the polymer portion.

A large number of slightly different compositions means that the ratio of the constituent monomer units in a part or all of the copolymer part changes continuously, and the polymerizable unsaturated monomer in the polymerization system is changed. Is obtained by gradually changing the composition of The reason for gradually changing the monomer composition in the polymerization system is, for example, that the second polymerization is carried out before or during the polymerization of the polymerization system containing the first polymerizable unsaturated monomer. It can be performed by gradually adding a polymerizable unsaturated monomer.

[0017] In the thermoplastic addition polymer of the present invention, it is possible to impart more various performances by combining three or more copolymer parts having different compositions. The thermoplastic addition polymer according to the second aspect of the present invention is one in which the thermoplastic addition polymer according to the first aspect is specified by physical properties. According to the second aspect, the thermoplastic addition polymer of the present invention contains two or more different polymerizable unsaturated monomer units, has a number average molecular weight of 4,000 to 1,000,000, It has only one glass transition temperature peak having a width of 50 ° C. or more, and has a parallel light transmittance of 85% or more. In a second aspect, the thermoplastic addition polymer preferably comprises 2
It has a number average molecular weight of 0000 to 200,000,
It has only one glass transition temperature peak having a width of 0 ° C. or more, and has a parallel light transmittance of 90% or more. One example of such a thermoplastic addition polymer is the thermoplastic addition polymer according to the first aspect.

The two or more different polymerizable unsaturated monomer units contained in the thermoplastic addition polymer according to the second embodiment of the present invention include the first monomer described in the description of the first embodiment. Unit and a second monomer unit. The thermoplastic addition polymer of the present invention has a number average molecular weight of 4,000 to 1,000,000. When the number average molecular weight is lower than the above range, physical properties derived from the composition of the monomer units constituting the polymer are difficult to develop, and when the number average molecular weight is higher, the viscosity is high and the handling is difficult. In these respects, the number average molecular weight is 10,000.
~ 20,000, preferably 20,000 ~ 200,
000 is more preferred.

The thermoplastic addition polymer of the present invention has only one glass transition temperature peak having a width of 50 ° C. or more, preferably 80 ° C. or more, more preferably 100 ° C. or more. If the width of the glass transition temperature peak falls below the above range, the balance between the heat resistance and the toughness of the polymer will be poor. The width of the glass transition temperature peak is preferably 80 ° C. or more than 50 ° C. or more in terms of the balance between heat resistance and toughness, and more preferably 100 ° C. or more than 80 ° C. or more. In addition, the width of the glass transition temperature peak indicates a peak width measured by a differential scanning calorimeter (DSC).

[0020] The thermoplastic addition polymer of the present invention has a parallel light transmittance of 85% or more. When the parallel light transmittance is lower than the above range, it indicates that the phase separation state of the polymer is large. Parallel light transmittance is more than 85% or more than 90%
% Or more is preferred for use in applications requiring transparency. The parallel light transmittance is a visible light transmittance measured by a turbidimeter in the thickness direction of a 3 mm-thick flat plate obtained by injection-molding a thermoplastic addition polymer.

The thermoplastic addition polymer of the present invention has a sulfur atom of 0.005 when produced by the production method described below.
-4% by weight. If the amount of the sulfur atom is less than the above range, the number average molecular weight may be too large or a thermoplastic addition polymer having a desired structure may not be obtained. There is a possibility that physical properties derived from the composition of the above may not be easily exhibited. The preferred number average molecular weight of the target thermoplastic addition polymer is from 10,000 to 400,
Therefore, the number average molecular weight is preferably in the range of 20,000 to 2% by weight.
Since it is 00,000, the range of 0.02 to 1% by weight is more preferable. [Production method of thermoplastic addition polymer] The production method of the present invention includes a preparation step, an addition step, and a polymerization step.

The preparation step is a step of preparing a mixture containing the first polymerizable unsaturated monomer and a polyvalent mercaptan. The adding step is a step of gradually adding a second polymerizable unsaturated monomer having a composition different from that of the first polymerizable unsaturated monomer to the mixture. In the polymerization step, a radical polymerization of a mixture of the first polymerizable unsaturated monomer and the added second polymerizable unsaturated monomer is performed starting from the mercapto group of the polyvalent mercaptan during the addition step. It is a process.

The polyvalent mercaptan used in the present invention is a mercaptan having two or more mercapto groups per molecule, and a mercaptan in which the number of mercapto groups per molecule is 2, 3,. Divalent mercaptan, trivalent mercaptan, ... Examples of the polyvalent mercaptan include diesters of diols such as ethylene glycol and 1,4-butanediol and carboxyl-containing mercaptans; compounds having three or more hydroxyl groups such as trimethylolpropane, pentaerythritol, and dipentaerythritol; Group-containing mercaptan polyester compounds; compounds having three or more mercapto groups such as trithioglycerin; 2-di-n-butylamino-4,6-dimercapto-S-triazine, 2,4,6-trimercapto- S-
Triazine polyvalent thiols such as triazine; a compound obtained by adding hydrogen sulfide to a plurality of epoxy groups of a polyepoxy compound to introduce a plurality of mercapto groups; an ester of mercaptoethanol with a plurality of carboxyl groups of a polycarboxylic acid And the like, and any of them can be used alone or in combination of two or more. Here, the carboxyl group-containing mercaptans are compounds having one mercapto group and one carboxyl group, such as thioglycolic acid, mercaptopropionic acid, and thiosalicylic acid.

The polyvalent mercaptan used in the present invention is
From the viewpoint of efficiently producing a thermoplastic addition polymer, and from the viewpoint of enhancing the performance of the obtained polymer by introducing a structure radially extending from the same center, preferably 2 to 10 mercapto groups (I.e., di- to divalent mercaptans), more preferably 3 to
Compounds having 6 mercapto groups (that is, 3 to 6
Mercaptan). Mercaptans having only one mercapto group do not provide a radially extended structure of the polymer portion. Mercaptans having three or more mercapto groups are preferred because they produce highly compatible thermoplastic addition polymers and make phase separation more difficult. A mercaptan having more than 10 mercapto groups does not have a structure radially extending from the same center, and thus may not exhibit desired physical properties.

The first polymerizable unsaturated monomer and the second polymerizable unsaturated monomer which can be used in the present invention are those which form a homopolymer or a copolymer by radical polymerization. Any of these monomers can be used. For example, (meth) acrylic acid; alkyl (meth) acrylate having 1 to 30 carbon atoms, hydroxyethyl (meth)
(Meth) acrylates represented by acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, and the like; α-methyl Styrene monomers represented by styrene, vinyl toluene, styrene, etc .; vinyl ether monomers represented by methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, etc .; fumaric acid, monoalkyl esters of fumaric acid, dialkyl fumaric acid Ester; maleic acid, monoalkyl ester of maleic acid, dialkyl ester of maleic acid; itaconic acid, monoalkyl ester of itaconic acid, dialkyl ester of itaconic acid; Ronitoriru, butadiene, isoprene, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl ketones, vinyl pyridine, and the like can be illustrated vinylcarbazole, alone either, or may be used in conjunction more.

According to the production method of the present invention, first, a mixture containing a first polymerizable unsaturated monomer and a polyvalent mercaptan is prepared. The first polymerizable unsaturated monomer may be a single monomer or a mixture of two or more polymerizable unsaturated monomers. The mixture containing the first polymerizable unsaturated monomer and the polyvalent mercaptan may further contain a medium in which the monomer and the mercaptan are dissolved and / or dispersed. The medium may be any medium in which the monomer and the obtained polymer are soluble. The amount of the medium is, for example, 0 to 200% by weight, preferably 0 to 100% by weight, based on the total amount of the first polymerizable unsaturated monomer and the second polymerizable unsaturated monomer.
It is. Exceeding the above range is not industrially preferable because the polymerization rate decreases and the cost in terms of solid content increases.

In the addition step, the second polymerizable unsaturated monomer is gradually added to the mixture prepared in the preparation step. The second polymerizable unsaturated monomer has a composition different from that of the first polymerizable unsaturated monomer, and may be a single monomer or two or more polymerizable unsaturated monomers. It may be a mixture of bodies. According to the production method of the present invention, the polymer capable of forming the first polymerizable unsaturated monomer and the polymer capable of forming the second polymerizable unsaturated monomer are incompatible. Even, for example, 8
A thermoplastic addition polymer having a parallel light transmittance of 5% or more, preferably 90% or more can be obtained. Here, that the polymers are not compatible means that the mixture of the polymers has undergone phase separation, and has a form such as a sea-island structure.

During the addition step, a mixture of the first polymerizable unsaturated monomer and the second polymerizable unsaturated monomer undergoes radical polymerization starting from the mercapto group of the polyvalent mercaptan.
By this radical polymerization, in each molecule of the polyvalent mercaptan, one or more sulfur residues of a mercapto group are added to a copolymer portion having a composition corresponding to the monomer composition of the polymerization system at the time of the reaction. A product with one end attached is obtained. The monomer composition of the polymerization system changes with the addition of the second polymerizable unsaturated monomer. Accordingly, the composition of the copolymer portion changes continuously. In order to efficiently bind one end of the copolymer moiety to the sulfur residue, it is preferable not to add a polymerization initiator more than necessary in the polymer system.

In the present invention, between the preparation step and the addition step, as a prepolymerization step, radical polymerization of only the first polymerizable unsaturated monomer can be carried out starting from the mercapto group of the polyvalent mercaptan. It is. By this radical polymerization, a product in which one end of a copolymer portion having one composition is bonded to one or a plurality of sulfur residues of a mercapto group in each molecule of the polyvalent mercaptan is obtained.

In the present invention, the radical polymerization can be carried out by any addition polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, which are ordinary radical polymerization methods. The polymerization temperature is preferably from 30 to 200 ° C., and more preferably 8 which allows stable polymerization without using a polymerization initiator.
0-150 ° C.

In the present invention, a conventional radical polymerization initiator for polymerization (for example, an azo-based polymerization initiator such as 2,2'-azobisisobutyronitrile and 2,2'-azobiscyclohexanecarbonitrile); A peroxide polymerization initiator such as benzoyl) can be used, but it is usually 1/3 or less, preferably 1/1, by weight of the polyvalent mercaptan.
0 or less, more preferably not used. The reason is as follows. When the polymerization initiator is used in a larger amount than the above ratio, in addition to the copolymer portion extended from the polyvalent mercaptan that gives the thermoplastic addition polymer, a large amount of the copolymer extended from the polymerization initiator is generated, and the thermoplastic Because the production efficiency of the addition polymer decreases, and the polymerization stability of the bulk polymerization, which is an industrially cheaper production method, deteriorates, a runaway reaction occurs, and in the worst case, there is a risk of explosion. is there.

As a production procedure, the polymerization rate is 0 to 50%, preferably 10 to 50%, with or without radical polymerization of the first polymerizable unsaturated monomer in the presence of polyvalent mercaptan.
After reaching ３０30%, the second polymerizable unsaturated monomer is gradually added. The polymerization rate of the first polymerizable unsaturated monomer at the start of the addition of the second polymerizable unsaturated monomer, and the time during which the second polymerizable unsaturated monomer is added are targeted. It is preferable to appropriately change the composition according to the composition of the copolymer portion of the thermoplastic addition polymer. For example, if a copolymer portion derived from the first polymerizable unsaturated monomer is required, the addition of the second polymerizable unsaturated monomer may be started at a high polymerization rate. If the copolymer portion derived from the first polymerizable unsaturated monomer is not necessary, the addition of the second polymerizable unsaturated monomer may be started simultaneously with the start of the polymerization. If a copolymer portion derived from the second polymerizable unsaturated monomer is required, the second polymerizable unsaturated monomer may be added at a rate relatively lower than the polymerization rate. If the copolymer portion derived from the second polymerizable unsaturated monomer is not required, the second polymerizable unsaturated monomer may be added at a speed relatively higher than the polymerization rate.

The second polymerizable unsaturated monomer is gradually added by dropping or the like. The rate of addition may be uniform or may vary, but is preferably uniform. When the second polymerizable unsaturated monomer is added after the polymerization rate exceeds the above range, the copolymer portion generated from the first polymerizable unsaturated monomer becomes too large and phase separation occurs. There is a possibility that a thermoplastic addition polymer is formed and becomes opaque. If the second polymerizable unsaturated monomer is added before the polymerization rate has reached the above range, the copolymer portion corresponding to the first polymerizable unsaturated monomer may hardly be produced, It is not preferred when a copolymer portion corresponding to the first polymerizable unsaturated monomer is required.

In the production method of the present invention, the monomer composition in the polymerization system is gradually changed by gradually adding the second polymerizable unsaturated monomer. As a result, the composition of the obtained copolymer portion gradually changes, and a thermoplastic addition polymer having a number of slightly different compositions (gradient compositions) can be obtained. Moreover, since radical polymerization is carried out starting from the mercapto group of the polyvalent mercaptan, a thermoplastic addition polymer in which a copolymer portion having an arbitrary composition is bonded to the polyvalent mercaptan portion by the valency of the mercapto group is obtained.

After completion of the addition of the second polymerizable unsaturated monomer,
If necessary, radical polymerization for aging can be performed. According to the production method of the present invention, for example, 85%
As described above, a thermoplastic addition polymer having a parallel light transmittance of preferably 90% or more is obtained. According to the production method of the present invention, the thermoplastic addition polymer according to the first aspect of the present invention or the thermoplastic addition polymer according to the second aspect of the present invention can be obtained.

[0036]

EXAMPLES Examples of the present invention and comparative examples outside the scope of the present invention will be shown below, but the present invention is not limited to the following examples. In the following, “%” means “% by weight” and “parts” means “parts by weight”. The number average molecular weight (Mn) is
It was determined in terms of polystyrene by gel permeation chromatography (GPC).

The width of the glass transition temperature peak is
Differential scanning calorimeter "DSC" manufactured by Perkin Elmer
The temperature (° C.) at which the DSC chart obtained from “−7” rises from the background level and the temperature (° C.) at which the DSC chart returns to the background level are examined. Return temperature and indicated by.

The parallel light transmittance was determined by measuring two 100 μm-thick polyethylene terephthalate (PET) films
After placing the spacers facing each other with a spacer of mm in between, filling the polymer between the films with an injection molding machine and cooling and solidifying the film, use a turbidity meter ND-1001DP of Nippon Denshoku Industries Co., Ltd. in the thickness direction. The transmittance was measured by irradiating visible light, and the measured value was corrected by the parallel light transmittance of two PET films.

The amount of sulfur atoms was determined by absorbing SO ₂ produced by high-temperature combustion of the polymer in an iodine solution and then performing titration. The amount of the monomer unit was determined by subtracting the value of the monomer composition in the polymerization system determined by gas chromatography from the total monomer composition added. (Example 1) 285 parts of methyl methacrylate, 15 parts of acrylic acid, and 30 parts of butyl acetate were placed in a 2-liter four-necked flask equipped with a nitrogen inlet tube, a dropping funnel, a thermometer, and a cooling tube.
0 parts, 5 parts of pentaerythritol tetrakisthioglycolate, and 0.1 part of azobisisobutyronitrile were charged, and the temperature was raised to 80 ° C. while stirring under a nitrogen atmosphere to initiate polymerization. Thirty minutes after the start of the polymerization (at this time, the polymerization rate was 21%), a monomer mixture composed of 665 parts of butyl acrylate and 35 parts of acrylic acid was dropped from the dropping funnel over 4 hours. After completion of the dropwise addition, stirring was further continued for 1 hour, and then the polymerization was stopped. After termination of polymerization,
The polymer was melted from the reaction mixture using a twin screw extruder to remove volatile components. The monomer composition over time of the polymerization system was measured by gas chromatography. The polymerization rate was determined from the monomer composition of the polymerization system and the amount of all monomers added up to the time of measurement. The number average molecular weight (Mn), the width of the glass transition temperature peak, the parallel light transmittance, and the amount of the monomer unit of the obtained polymer were measured. The amount of residual mercapto groups was measured by a colorimetric method (Ellman method). Table 1 shows the results of these measurements.

[0040]

[Table 1]

It is obtained from a decrease in the amount of the residual mercapto group over time, an increase in the molecular weight of the polymer over time, an increase in the peak width of the polymer glass transition temperature over time, and a change in the composition of the residual monomer over time. The polymer obtained is poly (methyl methacrylate / acrylic acid) (methyl methacrylate / acrylic acid # 95 /
5 (weight ratio)) about 6%, poly (butyl acrylate / acrylic acid) (butyl acrylate / acrylic acid 95/5)
(Weight ratio)), and it was confirmed that the remaining copolymer portion was a block polymer having a gradient composition of both compositions and extending in a star shape from mercapto residues.

Example 2 A device similar to that of Example 1 was charged with 250 parts of styrene, 250 parts of methyl methacrylate, 300 parts of butyl acetate, and 10 parts of dipentaerythritol hexakisthiopropionate, and stirred under a nitrogen atmosphere. While the temperature was raised to 105 ° C., polymerization was started. 20 minutes after the start of the polymerization (at this point, the conversion was 5.5%),
From a dropping funnel, a monomer mixture consisting of 475 parts of ethyl acrylate and 25 parts of methacrylic acid was dropped over 3 hours. After the completion of the dropwise addition, the polymerization was stopped after stirring was continued for another 3 hours. After termination of the polymerization, the polymer was melted from the reaction mixture using a twin-screw extruder to remove volatile components. Time-dependent monomer composition of the polymerization system, polymerization rate, amount of residual mercapto groups, number average molecular weight (Mn) of the obtained polymer, width of glass transition temperature peak, parallel light transmittance, monomer unit amount·
The amount of sulfur atoms was measured. Table 2 shows the results of these measurements.

[0043]

[Table 2]

From the decrease of the residual mercapto group over time, the increase of the polymer molecular weight over time, the increase of the polymer glass transition temperature peak width over time, and the change of the residual monomer composition over time,
About 3% of the obtained polymer was poly (methyl methacrylate / styrene) (methyl methacrylate / styrene @ 50/50 (weight ratio)) and poly (methyl methacrylate / styrene / ethyl acrylate / methacrylic acid) ( Methyl methacrylate / styrene / ethyl acrylate / methacrylic acid # 1
It was confirmed that a polymer portion having a gradient composition of both compositions containing about 20% (2/10/75/3 (weight ratio)) was a block polymer extending in a star shape from a mercapto residue.

(Comparative Example 1) A monomer mixture comprising 285 parts of methyl methacrylate, 50 parts of acrylic acid, 665 parts of butyl acrylate, and 2 parts of azobisisobutyronitrile was prepared in the same apparatus as in Example 1. And 200 parts of butyl acetate were charged, and the temperature was raised to 70 ° C. while stirring under a nitrogen atmosphere to initiate polymerization. Start of polymerization 30
After a minute (at this point, the polymerization rate was 21%), the remainder of the monomer mixture was added dropwise from the dropping funnel over 3 hours. Thirty minutes after the completion of the dropwise addition, 1 part of azobisisobutyronitrile was added, the temperature was raised to 80 ° C., and stirring was continued for 1 hour, and then the polymerization was stopped. After termination of the polymerization, the polymer was melted from the reaction mixture using a twin-screw extruder to remove volatile components. The polymerization rate, the number average molecular weight (Mn) of the obtained polymer, and the width of the glass transition temperature peak were measured. From these measurement results, the obtained polymer was found to have a conversion of 95.1%, a number average molecular weight Mn of 9.5 × 10 ⁴ , and methyl methacrylate / acrylic acid / butyl acrylate = 28.5 / 5.0. /66.5
However, the glass transition temperature peak width was −20 ° C. to −5 ° C., and the finger was completely different from the block polymer obtained in Example 1.

Comparative Example 2 Example 1 was repeated except that pentaerythritol tetrakisthioglycolate was not used, azobisisobutyronitrile was used in two parts, and the polymerization temperature was 70 ° C. Was repeated to carry out polymerization. After termination of the polymerization, the polymer was melted from the reaction mixture using a twin-screw extruder to remove volatile components. Degree of polymerization, number average molecular weight (M
n), the width of the glass transition temperature peak was measured. From these measurement results, the obtained polymer had a conversion of 94.6%,
Although the number average molecular weight Mn was 8.8 × 10 ⁴ , the gradient composition was the same as that of the block polymer obtained in Example 1, and the glass transition temperature peak width was −50 ° C. to 90 ° C., but it did not have a block structure. It was an opaque polymer.

(Comparative Example 3) In Example 2, after the polymerization time of the first polymerizable unsaturated monomer charged into the flask reached 3 hours (conversion rate: 80%), the second polymerization was carried out from the dropping funnel. The unsaturated polymerizable monomer was added all at once, and the mixture was further polymerized for 3 hours to obtain a polymer for comparison. After termination of polymerization,
From the reaction mixture, the polymer was melted using a twin screw extruder to remove volatile components. The obtained polymer had a polymerization rate of 92.0%.
3%, number average molecular weight Mn = 8.3 × 10 ⁴ , the same average composition as the polymer obtained in Example 2, two glass transition temperature peak widths of 5 to 15 ° C. and 75 to 90 ° C. The transition temperature peak width was narrow. In this polymer, the polymer portion radially extending from the polyvalent mercaptan portion was a block polymer having no gradient composition, and was phase-separated and clouded.

Example 3 Polymer 1 obtained in Example 1
A polymer solution obtained by dissolving 00 parts in 150 parts of butyl acetate is applied on a 25 μm-thick PET (polyethylene terephthalate) film so as to have a thickness of 20 μm, and butyl acetate is volatilized to obtain an adhesive tape. Was. The appearance, adhesive strength and holding power of the adhesive tape were examined, and the results are shown in Table 3.

Comparative Example 4 Polymer 1 Obtained in Comparative Example 1
A polymer solution obtained by dissolving 00 parts in 150 parts of butyl acetate is applied on a 25 μm-thick PET (polyethylene terephthalate) film so as to have a thickness of 20 μm, and butyl acetate is volatilized to obtain an adhesive tape. Was. The appearance, adhesive strength and holding power of the adhesive tape were examined, and the results are shown in Table 3.

(Comparative Example 5) Polymer 1 obtained in Comparative Example 2
A polymer solution obtained by dissolving 00 parts in 150 parts of butyl acetate is applied on a 25 μm-thick PET (polyethylene terephthalate) film so as to have a thickness of 20 μm, and butyl acetate is volatilized to obtain an adhesive tape. Was. The appearance, adhesive strength and holding power of the adhesive tape were examined, and the results are shown in Table 3.

The appearance was examined by visually observing whether the adhesive surface of the tape was transparent or cloudy. The adhesive strength was evaluated by a 180-degree peel strength measured at a tensile speed of 300 mm / min 20 minutes after a 25 mm width tape was stuck on a stainless steel (SUS) plate, and pressed back and forth with a 2 kg roller once. The measurement temperature was 23 ° C. The holding power is as follows: At 25 ° C, a 25mm x 25mm tape is stuck on a SUS plate,
20 minutes after reciprocating pressure bonding, temperature control at 40 ° C for 20 minutes,
A 1 kg load was applied to the tape support, and the evaluation was made based on the time (minutes) until the tape was peeled off the SUS plate and dropped.

[0052]

[Table 3]

Example 4 The damping performances of the block polymers having the same average composition obtained in Example 2 and Comparative Example 3 were compared. It is generally known that the vibration damping performance can be estimated from viscoelasticity data, and it is considered that the larger the tan δ over a wide frequency range and over a wide temperature range, the better. Then, as a result of measuring the temperature at which tan δ becomes 0.1 or more, the polymer of Example 2 is 0.3 or more between 5 and 90 ° C, and the polymer of Comparative Example 3 is 10 to 20 ° C and 80 ° C. It was 0.3 or more at ０．３90 ° C. Compared with the polymer of Comparative Example 3, the polymer of Example 2 can be expected to exhibit vibration damping performance over a wide temperature range and is transparent, so that it can be used in a wide range of applications.

Example 5 The same apparatus as in Example 1 was charged with 500 parts of styrene, 200 parts of butyl acetate and 10 parts of trimethylolpropane trithioglycolate, and the temperature was raised to 110 ° C. while stirring under a nitrogen atmosphere. Then, polymerization was started. 60 minutes after the start of polymerization (at this point, the polymerization rate is 10%
From the dropping funnel, and methyl methacrylate 50
0 parts were added dropwise over 3 hours. After completion of the dropwise addition, stirring was further continued for 1 hour, and then the polymerization was stopped. The conversion at this point was 60%. After termination of the polymerization, the polymer was melted from the reaction mixture using a twin-screw extruder to remove volatile components. The resulting polymer is about 7.6% polystyrene,
It is a star block polymer containing about 19% of poly (styrene / methyl methacrylate) (styrene / methyl methacrylate @ 40/60 (weight ratio)), and the remaining copolymer portion has a gradient composition of both components. It was confirmed that. Monomer composition over time of the polymerization system, polymerization rate, amount of residual mercapto groups,
The number average molecular weight (Mn), parallel light transmittance, amount of sulfur atom, and amount of monomer unit of the obtained polymer were measured. Table 4 shows the results of these measurements.

[0055]

[Table 4]

As is clear from Table 4, the obtained polymer was transparent with a parallel light transmittance of 91.5%. (Comparative Example 6) Polystyrene (glass transition point 100 ° C) 5
0 parts and poly (styrene / methyl methacrylate) (glass transition point 105 ° C, styrene / methyl methacrylate ≒ 40
/ 60 (weight ratio)) was melt-mixed to obtain a polymer mixture. The obtained polymer mixture has a parallel light transmittance of 77.
% Cloudiness.

As shown in Comparative Example 6, polystyrene having a close glass transition point and poly (styrene / methyl methacrylate) are hardly compatible with each other. A transparent polymer can be realized.

[0058]

According to the first aspect, the thermoplastic addition polymer of the present invention comprises a polyvalent mercaptan moiety and two or more different polymerizable unsaturated monomer units, and comprises a polyvalent mercaptan moiety. A star-shaped structure is made up of a polymer aggregate having a plurality of radially extending copolymer portions, and the copolymer portion has a composition that continuously changes throughout the polymer aggregate. A novel block polymer having a gradient composition having the following properties can be provided, the functionality can be enhanced without causing phase separation, and the transparency and mechanical strength are excellent.

According to the second embodiment, the thermoplastic addition polymer of the present invention contains two or more different polymerizable unsaturated monomer units, and has a number average molecular weight of 4,000 to 1,000,000. , Having only one glass transition temperature peak having a width of 50 ° C. or more, and having a parallel light transmittance of 85% or more, thereby having excellent transparency and mechanical strength.

The method for producing a thermoplastic addition polymer according to the present invention comprises the steps of: preparing a mixture containing a first polymerizable unsaturated monomer and a polyvalent mercaptan; An addition step of gradually adding a second polymerizable unsaturated monomer having a composition different from the polymerizable unsaturated monomer,
A polymerization step of performing a radical polymerization of a mixture of the first polymerizable unsaturated monomer and the added second polymerizable unsaturated monomer starting from the mercapto group of the polyvalent mercaptan during the addition step. By doing so, the functionality can be enhanced without causing phase separation, and a novel thermoplastic addition polymer excellent in transparency and mechanical strength can be industrially easily produced.

The production method of the present invention further comprises, between the preparation step and the addition step, a prepolymerization step of performing radical polymerization of the first polymerizable unsaturated monomer starting from the mercapto group of the polyvalent mercaptan. Therefore , the physical properties of the polymer corresponding to the first polymerizable unsaturated monomer can be more strongly expressed, and there is an additional advantage that a thermoplastic addition polymer having a wide range of performance can be obtained.

[0062] the production method of the present invention, since the rate of polymerization of the first polymerizable unsaturated monomer starts the <br/> addition step when it is 50 wt% or less, no phase separation heat A plastic addition polymer can be produced more reliably.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08F 293/00-297/08

Claims (6)

(57) [Claims] 1. A polyvalent mercaptan having a mercapto group
A polyvalent mercaptan portion, which is a remaining portion in which protons are dissociated , and a polymer aggregate having a plurality of copolymer portions composed of two or more different polymerizable unsaturated monomer units, The carbon atom at each one end of the plurality of copolymer portions is the polyvalent
Sulfur atom derived from mercapto group in mercaptan moiety
By bonding to the polymer moiety
Has a structure radially extending from the polyvalent mercaptan portion.
And two or more different polymerizable polymers constituting the copolymer portion.
The composition of the saturated monomer units is not interchangeable between the individual copolymer parts.
In total the aggregate of the polymer by different to have continuously changes, with the parallel light transmittance of 85% or more, thermoplastic addition polymer. 2. A glass transition temperature peak containing two or more different polymerizable unsaturated monomer units, having a number average molecular weight of 4,000 to 1,000,000, and having a width of 50 ° C. or more. A thermoplastic addition polymer that has only one and has a parallel light transmittance of 85% or more. 3. The thermoplastic addition polymer according to claim 2, wherein said glass transition temperature peak has a width of 80 ° C. or more. 4. The thermoplastic addition polymer according to claim 1, further comprising sulfur atoms in a range of 0.005 to 4% by weight. 5. A preparation step of preparing a mixture containing a first polymerizable unsaturated monomer and a polyvalent mercaptan, and a step of starting with a mercapto group of the polyvalent mercaptan as a starting point.
Prepolymerization for performing radical polymerization of the first polymerizable unsaturated monomer
A step of gradually adding a second polymerizable unsaturated monomer having a composition different from that of the first polymerizable unsaturated monomer to the mixture; and seen containing a polymerization step of performing radical polymerization of the mercapto group valence mercaptan as beginning first polymerizable unsaturated monomer and the second polymerizable unsaturated monomer, wherein the first polymer When the conversion of the unsaturated monomer is 50
A method for producing a thermoplastic addition polymer , wherein the addition step is started when the content is not more than% by weight . 6. The polymerization rate of the first polymerizable unsaturated monomer is as follows:
When the content is 10 to 30% by weight, the addition process is started.
A method for producing the thermoplastic addition polymer according to claim 5.