JP4338655B2 - Acrylate-based water-soluble polymer, production method and use thereof - Google Patents

Description

The present invention relates to an acrylate-based water-soluble polymer, a production method and use thereof. More specifically, the acrylate can be suitably used in various fields, in particular, can be suitably used for food additives, feed additives, etc., and exhibits an excellent function as a thickener, a loosening accelerator, etc. The present invention relates to a water-soluble polymer and a method for producing the same.

Acrylate-based water-soluble polymers are used, for example, as foods and feeds as thickeners and loosening accelerators. When used in such applications, higher quality is required in terms of viscosity, amount of remaining monomer, and the like. In addition, it is widely used in various fields as a thickener, adhesive, flocculant, hygroscopic agent, desiccant, surface modifier, etc. for pharmaceuticals, paints, civil engineering / architecture, and other general industries. Has been.

By the way, as a conventional acrylate polymer, a method by thermal polymerization is generally used. However, since the thermal polymerization method generally takes a long time to complete the polymerization, the productivity is not sufficiently excellent. There are many cases. Further, the probability that a branched component is generated increases with a longer polymerization time. For this reason, the thermally polymerized product contains a relatively large amount of insoluble matter. In order to solve this problem, a method for producing an acrylate polymer that is completely neutralized by thermal polymerization in the presence of a water-soluble compound having a specific cation and a specific hydroxyl group (see, for example, Patent Document 1) .) Is disclosed.
Although this polymer has a relatively low insoluble content and has been well evaluated, it has a limit in reducing the insoluble content. Furthermore, there is room for improvement in order to shorten the polymerization time, to make the productivity sufficiently excellent, and to make the quality sufficiently high so that it can be suitably used for food additives. .

On the other hand, as a method other than thermal polymerization, a method of obtaining a polymer by irradiating light is known. As a conventional production method using photopolymerization, a method in which acrylamide is mainly used and the amount of irradiation light is changed in the polymerization process is disclosed. For example, the light intensity of the first stage is 20 to 300 W / m ² , the light intensity of the second stage is 300 to 2000 W / m ² (for example, see Patent Document 2), and the light intensity using different types of lamps. (For example, refer to Patent Documents 3 and 4), adding an ultraviolet absorber and changing the amount of light (for example, refer to Patent Document 5), after the time when the surface temperature shows the maximum temperature, A method of irradiating the second stage is disclosed (for example, see Patent Document 6).
However, these documents do not disclose examples of polyacrylates. For example, in Patent Document 2, the specified amount of light is too high to be applied to polyacrylates. In the case of an acid salt, a polymer having a high viscosity cannot be obtained even when polymerized with such a light amount. In Patent Documents 3 and 4, it is necessary to use different types of lamps. When various polymers are produced, it is necessary to frequently replace the lamps, and the light intensity is gradually increased after the second stage. There is a risk that strict management is required.
Further, the purpose of addition of ultraviolet absorbers and change of light amount in Patent Document 5 is to control the reaction (runaway control), not to improve the quality of the obtained polymer, No investigation has been made from the viewpoint of increasing the viscosity. Furthermore, the addition of an ultraviolet absorber leads to a decrease in the purity of the product, and there is still concern about product safety.
And in patent document 6, although a cationic polymer is obtained, the peak temperature of Example 1 is as high as 98 degreeC, and when it applies to a polyacrylate, such a high peak temperature is high. A viscous product will not be obtained.

Moreover, what makes a methacryloyl group containing monomer essential (for example, refer patent document 7) and what makes a vinyl-type monomer essential (for example, refer patent document 8) are disclosed.
However, these documents also do not have examples of polyacrylates. For example, in Patent Document 7, the light intensity is increased 5 times when the reaction rate is 95 mol% or less (preferably 20 to 80 mol%). In the production of polyacrylate, if the light intensity is increased by a factor of 5 when the reaction rate is 20 to 80%, a polymer with high viscosity cannot be obtained, and the residual monomer can be reduced. It will not be connected. As described above, Patent Document 7 is used as an essential methacryloyl group-containing monomer different from an acrylate monomer, and the reduction of the residual monomer is secondary, and the insoluble matter is reduced. Is the main purpose. Further, in Patent Document 8, light irradiation is performed with an integrated light amount of 70,000 J / m ² or more in the second stage and after, and when the acrylate polymer is irradiated with such a high integrated light amount, the viscosity is reduced. Only low polymers will be obtained. In addition, the irradiation takes a long time and the productivity is also deteriorated. Thus, in the conventional photopolymerization method, the resulting acrylate-based water-soluble polymer is not necessarily sufficient in terms of viscosity, the amount of monomer remaining and the amount of insoluble matter, and is excellent in these respects. There was room for contrivance as an acrylate-based water-soluble polymer having physical properties and a method for producing such a polymer.
JP-A-6-56912 (page 2) Japanese Patent Publication No.55-12445 (Pages 1, 2, 5-9) Japanese Patent Laid-Open No. 10-298215 (pages 2, 4, 5) JP 11-35612 A (pages 2, 4, 5) Japanese Patent Laid-Open No. 55-50002 (pages 1, 2, 7) JP 63-295604 A (first, fourth, fifth pages) JP 2001-335603 A (2nd, 5-8 pages) Japanese Patent Laid-Open No. 2002-3518 (Pages 2, 6-9)

The present invention has been made in view of the above-described situation, and is excellent in safety, and can exhibit thickening and loosening acceleration with a low addition amount. It is an object to provide an acrylate-based water-soluble polymer that can be suitably applied to various uses such as feed and feed, and that can improve the texture and handleability, and a method for producing the same. Is.

As a result of various studies on the acrylate-based water-soluble polymer, the present inventors set the degree of neutralization to a specific range, the viscosity of the aqueous solution to a specific value or more, and the concentration and insolubility of the residual monomer. It has been found that a high-quality acrylate-based water-soluble polymer can be obtained when the concentration of the minute is not more than a specific value. In addition, various investigations have been made on the method for producing an acrylate-based water-soluble polymer, and when an acrylate-based water-soluble polymer is produced by photopolymerization under specific conditions, the polymerization time can be shortened. It was also found that the insoluble content having a branched structure can be reduced, and a high-quality acrylate-based water-soluble polymer can be obtained. Further, it has been found that according to the photopolymerization method, the light irradiation intensity and the irradiation time can be easily set and changed, so that the polymerization time can be further shortened and the productivity can be improved. Furthermore, since the acrylate-based water-soluble polymer obtained in this way can have a small amount of insoluble matter, in addition to the conventional use, it can be used for foods that require particularly high quality. It has been found that the present invention can be suitably used for feed applications and can exhibit excellent functions as a thickener, a loosening accelerator, and the like, and has reached the present invention.

That is, the present invention is a food additive or feed additive containing an acrylate-based water-soluble polymer, and the acrylate-based water-soluble polymer is mainly composed of an acrylate monomer. It is produced by polymerizing monomers, and has an aqueous solution viscosity of 0.2% by mass and 25 ° C. of 550 mPa · S or more, a residual monomer concentration of 1% by mass or less, The food additive or feed additive is sodium polyacrylate having an insoluble content of 0.15% by mass or less and a neutralization degree of 98 to 102 mol% .
The present invention is described in detail below.

The acrylate-based water-soluble polymer of the present invention has a viscosity of an aqueous solution containing the polymer at 0.2% by mass and 25 ° C. of 550 mPa · S or more. When the viscosity of the acrylate-based water-soluble polymer is less than 550 mPa, the viscosity is too low and the viscoelasticity is lowered when used for foods and the like, and the effects of the present invention may not be sufficiently exhibited. More preferably, it is 600 mPa * S or more, More preferably, it is 700 mPa * S or more. The upper limit of the viscosity is not particularly limited, but when it exceeds 1000 mPa · s, the insoluble matter generally tends to increase, which is not preferable.
The viscosity is measured with a B-type viscometer (reading after 30 rpm, 10 minutes) after adding 50 g of acrylate-based water-soluble polymer to 499 g of ion-exchanged water and stirring for 50 minutes to 25 ° C. It can ask for.

The acrylate-based water-soluble polymer has a residual monomer concentration (residual monomer concentration) of 1% by mass or less. In the acrylate-based water-soluble polymer, if the residual monomer concentration exceeds 1% by mass, the quality may be low, and the effects of the present invention may not be exhibited sufficiently. More preferably, it is 0.8 mass% or less, More preferably, it is 0.6 mass% or less.
The residual monomer concentration (residual monomer concentration) is the polyacrylic acid described in Food Additives 7th Edition, 436, 437, or Feed Additive Component Specification, etc., 10th Edition, 239, 240 It is measured by the following method described in the section of sodium purity test.

[Residual monomer]
About 1 g of this product is weighed precisely, put into a 300 ml iodine bottle, add 100 ml of water, and leave it for about 24 hours with occasional shaking to dissolve. To this solution, add exactly 10 ml of potassium bromate / potassium bromide test solution, shake well, add 10 ml of hydrochloric acid quickly, seal immediately and shake again well, then potassium iodide test solution on top of the iodine bottle Add about 20 ml and leave in the dark for 20 minutes. Next, loosen the stopper and pour the potassium iodide reagent solution, immediately seal it and shake well, then titrate with 0.1 mol / l sodium thiosulfate solution (indicator starch reagent solution 2 mL). Separately, a blank test is performed in the same manner, and the content is obtained by the following formula.
When the amount of residual monomer is determined by the following formula, the amount must be 1% or less.

Where a: consumption of 0.1 mol / l sodium thiosulfate solution in the blank test (ml)
b: Consumption of 0.1 mol / 1 sodium thiosulfate solution in this test (ml)

The insoluble content is preferably 0.15% by mass or less. In the acrylate-based water-soluble polymer, if the insoluble content exceeds 0.15% by mass, the quality may be low, and the effects of the present invention may not be sufficiently exhibited. More preferably, it is 0.10 mass% or less, More preferably, it is 0.07 mass% or less, Most preferably, it is 0.05 mass% or less. Most preferably, it is not included.
The insoluble matter was added to 499 g of ion-exchanged water, 1.0 g of an acrylate-based water-soluble polymer was added, stirred for 50 minutes, adjusted to 25 ° C., and filtered using a 500 μm mesh screen. Take out the insoluble matter of the following formula:
Insoluble matter (mass%) = {mass of insoluble matter (g) / 500 (g)} × 100
Is a value calculated based on In addition, in this specification, an insoluble content shall be a value measured within 1 minute after filtering the acrylate-type water-soluble polymer in aqueous solution with the said filter. In addition, filtration and weighing are performed under conditions of 25 ° C. and humidity of 60% or more.

The acrylate-based water-soluble polymer is also a group of neutralized groups when the total amount of acid groups and neutralized groups of the acrylate polymer is 100 mol%. It is preferable that content (neutralization degree) is 98 mol% or more and 102 mol% or less. That is, it is preferable that the acrylate-based water-soluble polymer is completely neutralized. By setting the degree of neutralization within the above range, there is an advantage that high viscosity is exhibited with a small addition amount. More preferably, it is 99 mol% or more and 101 mol% or less.

The group in the neutralized form is a group in which a dissociable hydrogen ion in an acid group is substituted with another cation. Therefore, the neutralization degree can be obtained by, for example, the monomer component forming the acrylate-based water-soluble polymer is x mol of acrylic acid, y mol of sodium acrylate as a salt of acrylic acid, and a nonionic monomer Assuming that n moles of the body are contained and all of them are polymerized, the nonionic monomer is not ionic and is not in a neutralized form, and therefore, it is obtained by the following formula.

In the above formula, the denominator is the sum of the number of moles of the acid group amount used for the production of the acrylate-based water-soluble polymer and the neutralized base amount. The molecule is the sum of the neutralized form base weight and the number of moles of excess cation present beyond the neutralization point. According to the above formula, the degree of neutralization (the content ratio of the neutralized group) can be obtained as mol%.

The present invention is also a method for producing an acrylate-based water-soluble polymer by photopolymerization of an acrylate-based monomer, which includes an acrylate-based monomer, a polymerization initiator, etc. Adjusting the pH of the polymerization solution for polymerization to 7.5 to 11.0, and irradiating with near ultraviolet rays of 10 W / m ² or less in the presence of a photopolymerization initiator, followed by 10 W / It is also a method for producing an acrylate polymer comprising a step of completing polymerization by irradiating near ultraviolet rays exceeding m ² . Such a manufacturing method is also a preferable manufacturing method of the acrylate-based water-soluble polymer of the present invention described above. That is, the acrylate-based water-soluble polymer is an acrylate-based water-soluble polymer produced by photopolymerization, which is also a preferred embodiment of the present invention.

The manufacturing method includes a step of polymerizing by irradiating near ultraviolet rays of 10 W / m ² or less and a step of completing polymerization by irradiating near ultraviolet rays exceeding 10 W / m ² . By irradiating near-ultraviolet rays having different intensities in two stages as described above, the polymerization of the monomer is promoted, and the resulting polymer can be made to have a high viscosity and remain in the polymer. Monomers can be reduced, and the resulting acrylate-based water-soluble polymer can have high quality as described above.

As the step of polymerizing by irradiating the first near ultraviolet ray, the irradiation intensity is preferably 10 W / m ² or less. When it exceeds 10 W / m ² , the amount of light is too high to obtain a sufficiently high viscosity polymer, and the insoluble content may not be reduced. More preferably, it is 8 W / m ² or less, and further preferably 6 W / m ² or less. The lower limit is preferably 1 W / m ² or more. If it is less than 1 W / m ² , the polymerization reaction may not be promoted sufficiently. More preferably, it is 1.5 W / m ² or more, and further preferably 2 W / m ² or more.

In the polymerization step, the irradiation time of near ultraviolet rays of 10 W / m ² or less is preferably 15 minutes or more. If the irradiation time is less than 15 minutes, the polymerization reaction cannot be sufficiently promoted, and a high-viscosity polymer may not be obtained. More preferably, it is 20 minutes or more, More preferably, it is 25 minutes or more. The upper limit of the irradiation time is preferably less than 100 minutes, and if it is 100 minutes or more, the productivity is lowered and the effects of the present invention cannot be sufficiently obtained. More preferably, it is less than 80 minutes, More preferably, it is less than 60 minutes.

As a process for completing the polymerization by irradiating near-ultraviolet rays in the second stage, it is preferable that the irradiation intensity exceeds 10 W / m ² . When it is 10 W / m ² or less, there is a possibility that the amount of remaining monomer is not sufficiently reduced because the light amount is too low. More preferably, there shall exceed 12W / ^{m 2,} more preferably in excess of 15W / ^{m 2.} The upper limit is preferably 100 W / m ² or less. If it exceeds 100 W / m ² , the irradiation intensity is too strong and the remaining monomer may not be sufficiently reduced. More preferably, it is 80 W / m < ² > or less, More preferably, it is 50 W / m < ² > or less.
The irradiation time of the near-ultraviolet ray in the second stage is not particularly limited as long as the remaining monomer can be sufficiently reduced, but is preferably 1 to 30 minutes. More preferably, it is 3-20 minutes, More preferably, it is 5-15 minutes.

As an apparatus for irradiating near ultraviolet rays in the polymerization step, for example, Neoarc (N), Neoarc (W), Neoarc (WW), Master Color CDM (3000K), Master Color CDM (4200K), Neoarc Beam (N) , Neoarc beam (WW), Neoarc beam (for outdoor use), Neoarc E base (N), Neoarc E base (WW), HQI lamp (D), HQI lamp (NDL), HQI lamp (WDL), Dyna beam 2, sunshine lamp, HL-neohalide 2 (transparent type), HL-neohalide 2 (diffusion type), HL-neohalide (transparent type), HL-neohalide (diffusion type), neohalide lamp (transparent type), neohalide lamp (Diffusion type), Color HID lamp (B), Color HID lamp (G), Neo color ( Color rendering type), Neo color (high saturation type), HL-Neolux D, Twin Neolux L, Twin Neolux, HL-Neolux, Neolux, Fluorescent mercury lamp, Incandescent fluorescent mercury lamp, Transparent mercury lamp Black light mercury lamp, chalkless mercury lamp, and the like. Further, the wavelength region of near ultraviolet rays is preferably 300 nm or more and preferably 500 nm or less. When ultraviolet rays having a wavelength of less than 300 nm are irradiated, the polymerization reaction may be accelerated, and an acrylate polymer having a high viscosity and a small amount of residual monomer may not be obtained.

In the above production method, the irradiation intensity of near ultraviolet rays is changed during polymerization by irradiating near ultraviolet rays, but the polymerization is started by adjusting the irradiation intensity to be 10 W / m ² or less. It is preferable. In the present specification, the near-ultraviolet light irradiation intensity is the light irradiation intensity measured on the upper surface of the reaction liquid irradiated with near-ultraviolet light, that is, the reaction liquid surface. The light irradiation intensity can be measured with the following light meter.
Apparatus: UV meter Manufacturer: Custom Co., Ltd. Model: Main unit UVA-365
Sensor UV sensor (Spectra response 300nm to 400nm)
In addition, as a problem related to the intensity of near-ultraviolet rays, there is a problem that polymerization control becomes difficult if the intensity is too strong, that is, a quality problem that bumping problem and insoluble matter tend to increase. By reducing the strength first and then increasing the strength, it is also advantageous for such a problem.

As a method of changing the intensity of near ultraviolet rays, a method using ultraviolet lamps having different irradiation intensities, a method of increasing or decreasing the irradiation intensity by inverter control, a method of installing a light reducing plate between the ultraviolet lamp and the polymerization liquid, etc. Thus, the irradiation intensity of near ultraviolet rays can be changed. At the laboratory level, for example, as shown in FIGS. 2 and 3, an ultraviolet lamp with different irradiation intensity is used, and the irradiation intensity is increased by adding a reflective shade to the ultraviolet lamp at the second stage of irradiation. Can be changed. In addition, when a belt polymerization method is used as the polymerization step, the near-ultraviolet radiation intensity can be changed by installing a light-reducing plate such as a punching metal between the belt and the ultraviolet lamp. Even in the case of using a plurality of different light-attenuating plates, the irradiation intensity can be appropriately changed, so that near-ultraviolet rays having different intensities can be irradiated in two stages, and the method of the present invention Can be used.

In the said polymerization process, it is preferable to suppress the peak temperature of a polymerization liquid to 70 degrees C or less.
When the peak temperature of the polymerization solution exceeds 70 ° C., the polymerization reaction proceeds excessively, and the resulting polymer may not have a sufficiently high viscosity. More preferably, it is 65 degrees C or less, More preferably, it is 60 degrees C or less. As a minimum of the peak temperature of a polymerization liquid, what is necessary is just the temperature from which a viscosity becomes sufficient, and it is preferable that it is 25 degreeC or more. More preferably, it is 30 degreeC or more, More preferably, it is 35 degreeC or more. The peak temperature is normally achieved in the initial near-ultraviolet irradiation, but there is no time limit to reach the peak temperature.

The acrylate-based water-soluble polymer in the present invention is a polymer obtained by polymerizing a monomer component essentially composed of an acrylate monomer composed of acrylic acid and / or acrylate. .
The acrylate monomer represents acrylate and a mixture of acrylate and a small amount of acrylic acid. As the acrylate, neutralized product obtained by neutralizing acrylic acid with monovalent metal, divalent metal, ammonia, organic amine, etc., that is, sodium acrylate, potassium acrylate, magnesium acrylate, calcium acrylate, acrylic Ammonium acid is preferred. Among these, sodium acrylate is preferable. The acrylate monomers may be used alone or in combination of two or more.
The monomer having the acrylate monomer of the present invention as a main component means that the amount of the monomer component as a raw material used is 100 mol%, and the acrylate monomer is 80 mol%. It is preferable that it is used exceeding.
In addition, in the case of uses other than food additives and feed additives, the monomer component may contain other monomers than acrylate monomers as required. In the case of uses other than food additives and feed additives, the amount of monomers other than acrylate monomers is preferably 20 mol% or less in the total monomers. More preferably, it is 10 mol% or less, More preferably, it is 5 mol% or less, Most preferably, it is 1 mol% or less.

The concentration in the reaction solution at the time of polymerization of the monomer component, that is, the concentration in the reaction solution at the start of polymerization of the monomer component, that is, in the polymerization solution containing an acrylate monomer, is 30 to 42 mass. % Is preferred. More preferably, it is 33-40 mass%. More preferably, it is 35-38 mass%.
In addition, the density | concentration of the monomer component in said reaction liquid calculates | requires the reaction liquid containing all the monomer components used for superposition | polymerization as 100 mass%.

In the said manufacturing method, it is preferable to adjust and adjust the pH of the said polymerization liquid to 7.5-11.0. If the pH of the polymerization solution is less than 7.5, the viscosity of the produced polymer aqueous solution may be lowered after the polymerization. If the pH exceeds 11.0, the viscosity of the polymer aqueous solution is lowered. Residual monomer may increase. More preferably, it is 8.0-10.5, More preferably, it is 8.5-10.0. The pH of the polymerization solution is a value measured at 25 ° C.

The polymerization step performed using the polymerization solution is preferably polymerized using a photopolymerization initiator. By polymerizing using a photopolymerization initiator, the insoluble content can be greatly reduced, the polymer can be made highly viscous, and the amount of remaining monomer can be reduced. Can do.
The photopolymerization initiator is not particularly limited as long as it exhibits its effects, but an azo initiator is preferable. As the azo initiator, 2,2′-azobis (2-amidinopropane), 2,2′-azobis (N, N′-dimethyleneisobutylamidine), 2,2′-azobis [2- (5- Methyl-2-imidazolin-2-yl) propane], 1,1′-azobis (1-amidino-1-cyclopropylethane), 2,2′-azobis (2-amidino-4-methylpentane), 2, 2'-azobis (2-N-phenylaminoamidinopropane), 2,2'-azobis (1-imino-1-ethylamino-2-methylpropane), 2,2'-azobis (1-allylamino-1- Imino-2-methylbutane), 2,2'-azobis (2-N-cyclohexylamidinopropane), 2,2'-azobis (2-N-benzylamidinopropane) and its hydrochloric acid, sulfuric acid, vinegar 4,4'-azobis (4-cyanovaleric acid) and its alkali metal salts, ammonium salts, amine salts, 2- (carbamoylazo) isobutyronitrile, 2,2'-azobis (isobutyramide), etc. 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis [2-methyl-N- (1,1'-bis (hydroxymethyl) ethyl) propion Amide], 2,2′-azobis [2-methyl-N-1,1′-bis (hydroxyethyl) propionamide] and the like are preferable. Among these, azo-based water-soluble initiators such as 2,2′-azobis-2-amidinopropane dihydrochloride are more preferable. As described above, in the polymerization step, a method for producing an acrylate polymer in which the polymerization initiator is an azo water-soluble initiator. An azo water-soluble initiator is also a preferred embodiment of the present invention.

As the photopolymerization initiator, a photopolymerization initiator other than the azo-based water-soluble initiator can be used. Such photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane. Eutectic mixture of -1-one, 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184) and benzophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1 -Propan-1-one, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)- Butanone-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (Irgacure 36) ) And 2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2 , 6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide (CGI403) and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173) A mixture of bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide (CGI403) and 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine 1: 1 mixture of oxide (CGI403) and 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 2-hydroxy-2-methyl- 1: 1 liquid mixture with 1-phenyl-propan-1-one (Darocur 1173), bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- ( 1H-pyrrol-1-yl) -phenyl) titanium,

Oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone], eutectic mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone, 4-methylbenzophenone and Liquid mixture with benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] and methylbenzophenone derivative Liquid mixture, 1- [4- (4-benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfanyl) propan-1-one, benzyldimethyl ketal, 2-hydroxy-2-methyl-1 -Phenyl-1-propanone, α-hydroxycyclohexyl-fur Nyl ketone, ethyl 4-dimethylaminobenzoate, acrylated amine synergist, benzoin (iso- and n-) butyl ester, acrylic sulfonium (mono, di) hexafluorophosphate, 2-isopropylthioxanthone, 4-benzoyl-4 ' -Methyldiphenyl sulfide, 2-butoxyethyl 4- (dimethylamino) benzoate, ethyl 4- (dimethylamino) benzoate,

Examples thereof include benzoin, benzoin alkyl ether, benzoin hydroxyalkyl ether, diacetyl and derivatives thereof, anthraquinone and derivatives thereof, diphenyl disulfide and derivatives thereof, benzophenone and derivatives thereof, and benzyl and derivatives thereof. These may be used alone or in combination of two or more, but are preferably used in combination with an azo-based water-soluble initiator.

The amount of the photopolymerization initiator used is preferably 0.0001 g or more and more preferably 1 g or less with respect to 1 mol of the monomer component used for polymerization. Thereby, the molecular weight and polymerization rate of the acrylate-based water-soluble polymer can be made sufficiently high. More preferably, it is 0.001 g or more and 0.5 g or less.

In the present invention, it is preferable to use a thermal polymerization initiator in combination with a photopolymerization initiator. By using the thermal polymerization initiator in combination, the amount of the remaining monomer can be reduced.
As the thermal polymerization initiator, a wide range of polymerization initiators soluble in an aqueous medium can be used. For example, hydrogen peroxide; persulfates such as ammonium persulfate, sodium persulfate, potassium persulfate; 2 Azo compounds such as 2,4'-azobis (2-amidinopropane) dihydrochloride, 4,4'-azobis- (4-cyanovaleric acid), 2,2'-azobisisobutyronitrile; An organic peroxide such as succinic acid is preferred. These can use 1 type (s) or 2 or more types. Among these, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, hydrogen peroxide, and the like are more preferable, and ammonium persulfate is more preferable.

As the usage-amount of the said thermal-polymerization initiator, 0.01-1 mass% is preferable with respect to 100 mass% of said monomer components. In order to accelerate the decomposition of these thermal polymerization initiators, an organic or inorganic reducing agent can be used in combination.
When using a reducing agent, 0.01-3 mass% is preferable with respect to 100 mass% of monomer components.

In the polymerization step, a chain transfer agent may be used as necessary. Examples of the chain transfer agent include sulfur-containing compounds such as sulfite (hydrogen) salts, thioglycolic acid, thioacetic acid, and mercaptoethanol; phosphorous acid compounds such as phosphorous acid and sodium phosphite; hypophosphorous acid and sodium hypophosphite Hypophosphorous acid compounds such as: alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and n-butyl alcohol. These may be used alone or in combination of two or more. Among these, a sulfurous acid (hydrogen) salt is preferable. More preferred is sodium bisulfite.
The amount of the chain transfer agent used may be appropriately set depending on the polymerization concentration, a combination with a photopolymerization initiator, and the like, but is preferably 0.0001 g or more with respect to 1 mol of the monomer component used for the polymerization. Moreover, 0.2 g or less is preferable. 0.001 g or more and 0.1 g or less is more preferable, and 0.005 g or more and 0.05 g or less is particularly preferable.

As the polymerization solvent, water is preferably used. In addition to water, a hydrophilic organic solvent or the like may be used in combination as appropriate. As the hydrophilic organic solvent, alcohols such as methanol and ethanol; ketones such as acetone, lower ethers and the like are preferable.

As a polymerization method in the polymerization step, a method by aqueous solution polymerization in which the reaction solution is in the form of an aqueous solution is preferable. In the aqueous solution polymerization, it is preferable to perform the polymerization in a state in which dissolved oxygen dissolved in the aqueous solution is removed in advance by, for example, a method of bubbling nitrogen gas. The polymerization operation method may be batch or continuous, but a method by static polymerization is preferred. In addition, there exists belt polymerization as one polymerization form in stationary polymerization.

The polymerization conditions in the polymerization step may be set as appropriate according to the composition of the monomer component, the type of photopolymerization initiator and the type and amount of thermal polymerization initiator added as necessary, The concentration of the monomer component in the reaction solution (monomer concentration) is 28% by mass or more, 60% by mass or less, more preferably 30 to 42% by mass, and still more preferably. Is 35-38 mass%. The above polymerization start time is when a reaction liquid containing a predetermined amount of monomer components is prepared and polymerized for polymerization. The monomer concentration is a concentration based on 100% by mass of the reaction solution. By increasing the monomer concentration, the thickening action of the polymer can be further enhanced. Further, it is more advantageous in terms of improving productivity. However, when the monomer concentration is too high, the insoluble content increases, which is not preferable. The polymerization peak temperature is −5 ° C. or higher and preferably 70 ° C. or lower, but the temperature at which the polymerization starts is preferably 50 ° C. or lower. More preferably, it is 30 degrees C or less, More preferably, it is 20 degrees C or less. A lower polymerization initiation temperature is advantageous in terms of productivity because there is no danger based on abnormal reactions such as bumping, and a reaction at a high concentration is facilitated. The above polymerization temperature is also an effective polymerization condition for improving the physical properties of the resulting acrylate-based water-soluble polymer.

In the present invention, photopolymerization is carried out in two stages, and the polymerization conditions such as pH and a photopolymerization initiator are used in combination, thereby further enhancing the aggregation action and thickening action of the resulting polymer. The effect of being able to reduce the amount of insoluble matter can be exhibited. Furthermore, the polymerization time can be shortened, which is advantageous in terms of productivity.

In the production method of the present invention, an acrylate-based water-soluble polymer that is a dried product can be obtained by drying the polymer obtained by the polymerization step preferably at 50 ° C. to 200 ° C. As a method for drying the polymer, for example, it is preferable to increase the surface area of the polymer or to dry under reduced pressure by a method such as cutting the polymer so as to be easily dried. When the drying temperature is lower than 50 ° C., the polymer may not be sufficiently dried. When the drying temperature is higher than 200 ° C., the polymer may be thermally cross-linked and the insoluble content may increase. Moreover, when higher than 220 degreeC, there exists a possibility that the cutting | disconnection of the polymeric principal chain or a crosslinking point may occur. Therefore, a more preferable drying temperature is 50 to 180 ° C. More preferably, it is 80-150 degreeC. In addition, what is necessary is just to set suitably as drying time according to the moisture content, drying temperature, etc. which are contained in a polymer.

The present invention further relates to a food additive or feed additive containing an acrylate-based water-soluble polymer, wherein the acrylate-based water-soluble polymer is mainly composed of an acrylate monomer. It is produced by polymerizing monomers, and has an aqueous solution viscosity of 0.2% by mass and 25 ° C. of 550 mPa · S or more, a residual monomer concentration of 1% by mass or less, The food additive or feed additive is sodium polyacrylate having an insoluble content of 0.15% by mass or less and a neutralization degree of 98 to 102 mol% .
As described above, the acrylate-based water-soluble polymer has a specific range of viscosity, residual monomer concentration, insoluble content, and neutralization degree. When it is added to a feed or feed, a suitable viscoelasticity is obtained, the safety is excellent, and an excellent thickening is exhibited with a small addition amount. Among these characteristics, since the insoluble matter is a small amount, it becomes high quality and is particularly useful for foods, feeds and the like. For example, when used as a thickener such as ice cream, the texture becomes smooth. Thus, the acrylate-based water-soluble polymer satisfies characteristics and standards required for food additives and feed additives. Such an acrylate-based water-soluble polymer can be suitably obtained by the above-described polymerization method.

The characteristics and standards required for the above-mentioned food additives and feed additives are described in the Food Additives Official Document (7th edition) and the Feed Additives Component Specifications (10th edition). As the characteristics of sodium acrylate, the following properties, confirmation test, purity test, dry raw material and ignition residue are listed.

[Properties] This product is white powder and does not smell.
[Confirmation test]
(1) Add 100 mL of water to 0.2 g of this product, stir well to dissolve, and use this as the sample solution. When 1 mL of calcium chloride test solution is added to 10 mL of this sample solution and shaken, a white precipitate is immediately formed.
(2) The residue obtained by ashing this product exhibits a qualitative reaction of sodium salt.

[Purity test]
(1) Free alkali Weigh 0.20 g of this product, add 60 ml of water, stir well to dissolve, add 3 ml of calcium chloride solution, heat on water bath for about 20 minutes, cool and filter. The residue on the filter paper is washed with water, the washing solution is combined with the filtrate, and water is further added to make 100 ml, which is used as a sample solution. When 50 ml of sample solution is taken and 2 drops of phenolphthalein test solution are added, the solution does not show a red color.

(2) Sulfate When taking 20 mL of the sample solution of (1) and adding 1 mL of dilute hydrochloric acid to test the sulfate, the amount should be less than the amount corresponding to 0.4 mL of 0.005 mol / L sulfuric acid ( 0.49% or less).

(3) Heavy metal When 1.0 g of this product is taken and tested by the heavy metal test method method 2, the amount must be below the amount corresponding to 2.0 mL of lead standard solution (20 ppm or less).
(4) Arsenic When 0.5 g of this product is taken and the test is conducted by the third method of the arsenic test method, it must conform to this (4 ppm or less).

(5) Residual monomer About 1 g of this product is weighed accurately, put into a 300 mL iodine bottle, added with 100 mL of water, shaken occasionally, and allowed to stand for about 24 hours to dissolve. Add exactly 10 mL of potassium bromate / potassium bromide test solution and shake well. Further, quickly add 10 mL of hydrochloric acid, seal immediately and shake well. Then, put about 20 mL of potassium iodide test solution on top of the iodine bottle. Leave for 20 minutes. Next, loosen the stopper and pour the potassium iodide reagent solution, immediately stopper and shake well, then titrate with 0.1 mol / L sodium thiosulfate solution (2 mL indicator starch reagent). Separately, when a blank test is performed by the same method and the amount of residual monomer is determined by the following formula, the amount must be 1% or less.

However, a: consumption of 0.1 mol / L sodium thiosulfate solution in the blank test (ml)
b: Consumption of 0.1 mol / L sodium thiosulfate solution in this test (ml)

(6) Low Polymer Add 200 mL of water to 2 g of this product, occasionally shake it and let it stand for about 24 hours to dissolve. While stirring this, 50 ml of 10 mol / L hydrochloric acid is added dropwise, and the mixture is heated for 30 minutes while stirring in a water bath at about 40 ° C. and then left for 24 hours. The resulting precipitate was filtered, one drop of phenolphthalein test solution was added to the filtrate, sodium hydroxide solution (2 → 5) was added until the filtrate turned slightly red, and then diluted hydrochloric acid (1 → 30). Add until the red color disappears. Next, 200 mL of water is added, and 25 mL of calcium chloride test solution is added dropwise with stirring, and then heated for 30 minutes while stirring in a water bath at about 40 ° C. The resulting precipitate is suction filtered with a glass filter of known weight (1G4), the residue is washed with about 10 mL of water three times, dried at 105 ° C. for 4 hours, and the content of low polymer is obtained by the following formula: The amount must be less than 5%.

[Loss on drying]
10.0% or less (1.5 g, 105 ° C., 4 hours)
[Remaining ignition heat]
76.0% or less after drying (1 g)

In the above standards, [purity test] (3) sulfate is required to be 0.48 g or less, and does not mean that it is included as an essential component. In the present invention, a persulfate as a thermal polymerization initiator is not used in the production process of an acrylate-based water-soluble polymer, and satisfies the above criteria.

The acrylate-based water-soluble polymer of the present invention meets the above-mentioned standards, and as its use, it is suitably applied to the food additives official document (5th edition) D-873, page 874. be able to.

[Use]
This product has a very high viscosity and is about 10 times as viscous at room temperature as other synthetic pastes. In particular, the fact that there is little change in viscosity with respect to heat treatment and neutral salts and organic acids, and that the viscosity increases on the alkali side are significant differences from other synthetic pastes. Therefore, the amount of this product used for food is very small, which is why it is limited to 0.2% or less as a thickener. However, since this product is an electrolyte, it must be noted that it is greatly affected by metal ions.
The physicochemical properties of this product for food can be enumerated as follows (2nd edition Food Additives Official Note 810, (1968) Kanehara Publishing).

(1) Strengthen protein adhesive strength in raw powder.
(2) The starch particles are linked together and dispersed and penetrated into the protein network.
(3) A dense substrate is formed on the dough, and the surface is smooth and glossy.
(4) Since a stable dough colloid is formed, leaching of soluble starch is prevented.
(5) Since water retention is strong, moisture is kept uniformly in the dough and drying is prevented.
(6) Improve the spreadability of the fabric.
(7) The oil and fat content in the raw material powder is dispersed in the dough and stabilized.

In short, interaction as an electrolyte acts on the protein, and by changing the protein structure, the viscoelasticity of the food can be increased and the structure can be improved. In particular, it is effective in improving the physical properties of flour-like dough such as noodles, and has a high utility value as an effective noodle improver when added in an amount of 0.05 to 0.1% to wheat flour.
Furthermore, this product is used as a polymer flocculant as a clarification accelerator for sugar solutions, salt water, beverages, etc., and recently it is used for recovering effective protein from wastewater at fish processing plants and purifying wastewater in pollution problems. It has been expanded.

The following are examples of actual food applications.
(1) Bread, cakes, noodles, macaroni, spaghetti, etc .: improved yield, improved texture and flavor.
(2) Aquatic product, Tsukudani, Canned food, Dry paste: Strengthening of tissue, preservation of freshness, imparting rich taste.
(3) Sauce, ketchup, mayonnaise, jam, cream, miso, soy sauce: as a thickener and stabilizer.

(4) Juice, liquor, etc .: dispersant.
(5) Ice cream, caramel, sheep kan, etc .: Improved taste and stability.
(6) Frozen food, processed fishery product: glaze processing agent.

The acrylate-based water-soluble polymer of the present invention can be suitably applied to the various uses described above. For example, the kneading, dipping, or spraying of the noodles improves the loosening of the noodles. Can be made. The acrylate-based water-soluble polymer can exert an excellent effect with a small addition amount, and thus does not adversely affect noodles and noodle soup.
Moreover, since there is little insoluble content, when using it for foodstuffs or feedstuffs, there exists an advantage that foodstuffs, such as noodles and ice cream, become smooth and a texture is improved. Moreover, when there is much the said insoluble content, when using it for the object for foodstuffs or feed, the malfunction that a taste falls will arise. In order to reduce the insoluble content, the acrylate polymer can be dissolved in water in advance and then used after removing the insoluble content with a filter such as a wire mesh. However, in this case, complicated management steps increase, which is not preferable.

When the above acrylate-based water-soluble polymer is used as a food additive, even if the acrylate-based water-soluble polymer is used alone, its effect is exhibited. By using together with at least one organic acid or a salt thereof, the dispersibility is improved and the loosening effect on the surface of the noodles is exhibited, so that the amount used can be further reduced.

The acrylate-based water-soluble polymer of the present invention can also be used for feed applications, for example, can be suitably used as an animal or fish feed additive. The acrylate-based water-soluble polymer of the present invention can be suitably used, for example, as an anti-gastric ulcer agent for animals such as pigs.
In addition, the following items are listed as specifications of the preparations in the specifications of ingredients for feed additives.

(Ingredient standard)
This product consists of sodium polyacrylate, albumin, casein, carrageenan, agar, xanthan gum, guar gum, gluten, rice bran meal, wheat flour, gelatin, dextrin, α-starch, corn flour, tracant gum, far celerin, bran, bentonite. , A powder in which silicic anhydride and its salts are mixed.

[Confirmation test]
Take an amount corresponding to 0.2 g of “sodium polyacrylate” according to the displayed amount of this product, and dry at 140 ° C. for 1 hour. Next, this preparation is put into a separatory funnel, 100 mL of carbon tetrachloride is added and shaken vigorously, and then left to stand for 5 minutes to separate a lower precipitation layer (sodium polyacrylate-containing layer). To this, 50 mL of ethanol / water mixture (1: 1) is added and stirred well, then allowed to stand for several minutes, and the upper layer is removed by suction. At this time, the sodium polyacrylate is separated into an intermediate band-like layer. Next, the intermediate layer is subjected to suction filtration with a glass filter (G3). At this time, the lower layer sediment is discarded. The residue on the funnel is then transferred to a 200 mL Erlenmeyer flask and dried. 100 mL of water is added to this, and it stirs well and melt | dissolves. Hereafter, the verification tests (1) and (2) of "sodium polyacrylate" apply mutatis mutandis.

Since the acrylate-based water-soluble polymer of the present invention has a small amount of residual monomer and a low concentration of insoluble matter, it is excellent in safety and has a thickening effect with a low addition amount. Can be obtained. Further, since the insoluble content is small, the texture is improved, so that it is excellent as a food additive or a feed additive.

The acrylate-based water-soluble polymer of the present invention has the above-described configuration, is excellent in safety, and can exhibit thickening and loosening acceleration with a low addition amount, improving texture and handling properties. Therefore, it can be suitably used for food additives or feed additives, and can also be suitably applied to various other uses. Moreover, the manufacturing method is a thing with good productivity, and can manufacture suitably the acrylate-type water-soluble polymer used for the said use.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

Example 1
As shown in FIG. 1, a 500 cc glass beaker (86 mmφ × 118H) equipped with a resistance temperature detector was charged with 63.2 g of a 37% by weight aqueous solution of sodium acrylate and 0.585 g of glycerin (GC). After adjusting the pH to 10.0, ion exchange water was added to make the total amount 64.5 g. A stirrer chip was introduced, and the top of the beaker was covered with one Saran wrap (manufactured by Asahi Kasei Kogyo Co., Ltd.). Next, the liquid in the beaker was bubbled with nitrogen through a thin pipe to remove oxygen in the liquid layer part and the lower part of the Saran wrap (the air layer part in the beaker. Next, 2,2′-azobis was used as a photopolymerization initiator. (2-Amidinopropane) hydrochloride (trade name V-50 manufactured by Wako Pure Chemical Industries, Ltd., 0.311 g of 4% by weight aqueous solution and 0.249 g of ammonium persulfate (APS) 0.2% by weight aqueous solution were added and mixed. The concentration of sodium acrylate in this polymerization solution was 36% by mass.

The amount of glycerin added was 2.5% by mass with respect to sodium acrylate. Moreover, the usage-amount of V-50 was 0.05g with respect to 1 mol of sodium acrylate. The amount of APS used was 0.002 g per 1 mol of sodium acrylate. The pH was 10.0 and the liquid temperature was 22 ° C. The liquid thickness was about 10 mm.
The polymerization solution was placed at the bottom of the near-ultraviolet lamp shown in FIG. 2 (Toshiba Lighting & Technology Co., Ltd., trade name: black light mercury lamp, model H100BL-L sideways, no reflection shade). In addition, the distance (49 cm) between the lamp and the upper surface of the polymerization solution is set in advance so that the light intensity at the upper surface position of the polymerization solution is 3.7 W / m ² .

In addition, the UV meter (model UVA-365) made from a custom company was used for the photometer.
Polymerization started immediately, and the peak temperature reached 57.5 ° C. in 21 minutes. After irradiating with a light intensity of 3.7 W / m ² until 23 minutes, the polymerization solution (gel-like) was irradiated with a near-ultraviolet lamp (trade name: black light mercury lamp, manufactured by Toshiba Lighting & Technology Co., Ltd.) (Model H400BL-L standing, with reflective shade). The distance (15 cm) between the lamp and the upper surface of the polymerization liquid (gel) is set in advance so that the light intensity at the upper surface position of the polymerization liquid (gel) is 17 W / m ² . After continuing the polymerization for 8 minutes at this light intensity, the light irradiation was terminated.
The water-containing gel thus obtained was cut into thin pieces with scissors and then dried at 150 ° C. for 1.5 hours using a hot air circulation dryer. Next, the dried product was pulverized with a table-type pulverizer and classified so as to pass a 850 μm mesh.

In this way, an acrylate-based water-soluble polymer (1) composed of sodium polyacrylate was obtained.
The viscosity of the acrylate-based water-soluble polymer (1) was measured as follows.
Add 499 g of ion-exchanged water to a 500 cc beaker, add 1 g of the acrylate-based water-soluble polymer (1) in terms of solid content while stirring with a magnetic stirrer, and then stir for 50 minutes at 100 rpm with a jar tester. And the temperature is adjusted to 25 ° C., and then measured with a B-type viscometer (reading after 30 rpm, 10 minutes). The viscosity of the acrylate-based water-soluble polymer (1) was 660 mPa · S.

The insoluble content of the acrylate-based water-soluble polymer (1) was measured as follows. That is, the water-soluble insoluble matter was taken out by filtering 500 g of the aqueous solution of the acrylate-based water-soluble polymer (1) after measuring the viscosity through a 500 μm mesh sieve. And this insoluble matter was weighed immediately (within 1 minute) so as not to dry, and the insoluble matter was calculated based on the following formula.

Insoluble matter (mass%) = {mass of insoluble matter (g) / 500 (g)} × 100
The filtration and weighing were performed at 25 ° C. and 60% humidity.
The insoluble content of the acrylate-based water-soluble polymer (1) was 0.05%.
The residual monomer of the acrylate-based water-soluble polymer (1) was measured by the method described in the section of sodium polyacrylate in the Food Additives Official Document. The residual monomer of the acrylate-based water-soluble polymer (1) was 0.38%.

Examples 2-4
Polymerization was performed in the same manner as in Example 1 except that the conditions shown in Table 1 were used, to obtain a polymer (gel). The polymer (gel) was treated in the same manner as in Example 1 and the physical properties were measured. The results are shown in Table 1.

Comparative Examples 1-4
Except for the conditions shown in Table 2, polymerization was performed in the same manner as in Example 1 to obtain a polymer (gel). The polymer (gel) was treated in the same manner as in Example 1 and the physical properties were measured. The results are shown in Table 2.

Comparative Example 5
A beaker with a capacity of 5 L was charged with 4865 parts of a 37% by weight aqueous solution of sodium acrylate and 45 parts of glycerin, and the pH was adjusted to 12.8 with a dilute aqueous sodium hydroxide solution while stirring. Subsequently, ion exchange water was added to make a total amount of 4989 parts. The dissolved oxygen was removed by bubbling nitrogen gas through this solution.
Next, under nitrogen gas bubbling, a polymerization solution was prepared by adding 11.1 parts of a 1% by weight aqueous solution of ammonium persulfate as a thermal polymerization initiator. The monomer concentration in the polymerization solution was 36% by mass. The amount of glycerin added was 2.5% by mass with respect to sodium acrylate. The amount of ammonium persulfate added was 0.0058 g per mole of sodium acrylate.

After the polymerization solution was charged into the polymerization vessel shown in FIG. 1 (Japanese Patent Laid-Open No. 11-35606), the glass cock was closed and a thermometer was inserted to seal the inside of the polymerization vessel. This polymerization container was immersed in a constant temperature water bath (heating device) adjusted to 35 ° C. in advance, and polymerization (aqueous solution stationary polymerization) was started. Therefore, the water bath temperature at the start of polymerization is 35 ° C.
After the polymerization vessel was immersed in a constant temperature water bath, the polymerization proceeded gradually, and the polymerization temperature reached a peak at 4.5 ° C. (peak temperature) 4.5 hours after the immersion. During this time, the water bath temperature was maintained at 35 ° C.
And after superposition | polymerization temperature reached peak temperature, the water bath temperature was hold | maintained at 35 degreeC for further 0.5 hour.

This terminated the primary reaction. Thereafter, the water bath temperature was raised from 35 ° C. to 75 ° C. in 0.2 hours. And it matured by hold | maintaining 75 degreeC for 1.5 hours, and superposition | polymerization (secondary reaction) was completed.
After completion of the polymerization, the polymerization vessel was cooled, the bolts and nuts were loosened, the mold was opened, and the contents were taken out. The content obtained was a transparent gel. The gel-like material was treated in the same manner as in Example 1 and the physical properties were measured. The results are shown in Table 2.

FIG. 1 is a view showing an embodiment of a polymerization apparatus for producing the acrylate-based water-soluble polymer of the present invention. FIG. 2 is a diagram showing an embodiment of the first photopolymerization step in the method for producing an acrylate-based water-soluble polymer of the present invention. FIG. 3 is a diagram showing an embodiment of the second-stage photopolymerization step in the method for producing an acrylate-based water-soluble polymer of the present invention.

Explanation of symbols

1, 13, 24: Saran wrap (Asahi Kasei Kogyo Co., Ltd.)
2: Beaker 3 with a capacity of 500 cc, 14: Resistance thermometer 4, 15, 25: Polymerization solution 11: Black light mercury lamp (H100BL-L), manufactured by Toshiba Lighting & Technology Co., Ltd. 12, 21: Lamp holder, Toshiba Lighting & Technology Corporation Product 22: Black light mercury lamp (H400BL-L), Toshiba Lighting & Technology Corp. 23: Reflection shade (SN-4057T), Toshiba Lighting & Technology Corp.

Claims (4)

A food additive containing an acrylate-based water-soluble polymer, the acrylate-based water-soluble polymer,
It is produced by polymerizing a monomer having an acrylate monomer as a main component, and has an aqueous solution viscosity at 25% by mass of 550 mPa · S or more, and a residual single amount. Food additive characterized by being sodium polyacrylate having a body concentration of 1% by mass or less, an insoluble content in water of 0.15% by mass or less, and a neutralization degree of 98 to 102 mol% . The food additive according to claim 1, wherein the acrylate-based water-soluble polymer is produced by photopolymerization. A feed additive comprising an acrylate-based water-soluble polymer, the acrylate-based water-soluble polymer,
It is produced by polymerizing a monomer having an acrylate monomer as a main component, and has an aqueous solution viscosity at 25% by mass of 550 mPa · S or more, and a residual single amount. Feed addition characterized by being sodium polyacrylate having a body concentration of 1% by mass or less, an insoluble content in water of 0.15% by mass or less, and a neutralization degree of 98 to 102 mol% object. The feed additive according to claim 3, wherein the acrylate-based water-soluble polymer is produced by photopolymerization.

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