JPH0623253B2 - Method for producing organic silicon resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a method for producing an organic silicon resin, particularly as a silicone pressure-sensitive adhesive, and as an intermediate raw material for silicone rubber, silicone oil, silicone release agents and the like. The present invention relates to a method for producing an organosilicon resin comprising a useful monofunctional siloxane unit and a tetrafunctional siloxane unit.

[Prior Art] An organosilicon resin (hereinafter MQ) composed of a monofunctional siloxane unit (hereinafter abbreviated as M siloxane unit) and a tetrafunctional siloxane unit (hereinafter abbreviated as Q siloxane unit).
(Abbreviated as "resin") is important as a silicone pressure-sensitive adhesive and as an intermediate raw material for silicone rubber compounds, particularly liquid silicone rubber compounds, silicone oil compounds, and silicone release agents.

However, the silicone pressure-sensitive adhesive made using MQ resin as one of the raw materials has little change in performance at high and low temperatures, has excellent heat resistance and cold resistance, and is nontoxic to living organisms. It is required to be active and to have excellent electrical characteristics. Since it is generally used in the form of a tape, it has a large adhesive force to the tape or sheet, that is, an anchoring force and a large cohesive force. It is desired that the pressure-sensitive adhesive strength is large, but this has a problem that it is difficult to manufacture a product having these properties in a well-balanced manner.

Then, this MQ resin has (CH ₃ ) ₃ SiC, (CH ₃ ) ₃ SiOSi (CH
₃ ) ₃ , (CH ₃ ) ₃ SiOH, (CH ₃ ) ₂ CH ₂ =
Organosilanes such as CHSiC and water glass, orthoalkyl silicates, and alkyl polysilicates as Q siloxane units are dropped into a reactor charged with water, toluene, isopropanol, and acid to hydrolyze, and acid-water is allowed to stand still. -Layer consisting of alcohol and MQ resin-
Separated into a layer consisting of toluene-alcohol, this MQ
After washing a layer consisting of resin-toluene-alcohol several times with hot water, the alcohol is dissolved in water and extracted, and then this MQ resin is subjected to alkali polymerization to remove the alkali catalyst, followed by dehydration and passing. Being manufactured.

[Problems to be Solved by the Invention] However, in the method for producing an MQ resin according to this conventional method,
Disadvantages are low MQ resin yield per batch and more alcohol needs to be used to prevent gel formation during the process, but more alcohol increases the amount of alcohol in the wastewater. Therefore, a large amount of cost is required for wastewater treatment, and a large amount of acid is used during hydrolysis, and this is discharged to the outside of the system as wastewater, which requires a large amount of equipment cost for this treatment. In addition, the MQ resin obtained in this way does not stabilize due to the process of easily gelling,
There is a drawback that the quality variation becomes large.

[Means for Solving the Problems] The present invention relates to a method for producing an MQ resin which solves the above disadvantages, which is represented by the general formula R ^{1 in a} reactor A).
_At least ^{one of} ₃ SiOSiR ¹ ₃ , R ¹ ₃ SiOR ² , R ¹ ₃ SiOH and /
Or R ¹ ₃ SiNHSiR ¹ ₃ (wherein R ¹ is a group selected from an alkyl group, an alkenyl group and an aryl group, R ² is a carbon number of 1 to 5)
An alkyl group of) and a general formula (R
² O) ₄ Si (R ² is the same as above) charged with organosilane or a partial hydrolysis-condensation product thereof, and a hydrolysis step in which acid and water are added dropwise to hydrolyze, B) an alkali metal carbonate is added to the reaction system. Primary neutralization step of adding hydrogen salt to neutralize acid and adding acid to maintain pH of system at 3 to 6, C) Alcohol by-produced in hydrolysis reaction and used for hydrolysis reaction After removing the excess water, a solvent substitution step of adding an aromatic hydrocarbon solvent, D) at least one hydroxide and / or carbonate of an alkali metal hydroxide, and / or a hydrogen carbonate salt are added and heated. Alkaline polymerization step to polymerize by, E) Acid treatment step to neutralize and remove the alkali polymerization catalyst with acid, F) Secondary neutralization step to remove the acid used in the acid treatment step, G) Free water in the system In the dehydration step to remove and H) primary neutralization step, acid treatment step, secondary neutralization step It forms a salt, over step, and a monofunctional siloxane units and tetrafunctional siloxane units, characterized in that it consists of capital formula for removing dehydrating agent used in the dehydration step [(R ¹ ₃ SiO _1/2 ) _m (SiO _4/2 ) _n ] (R ¹ , R
² is the same as the above), and relates to a method for producing an organic silicon resin having m / n (molar ratio) of 0.5 to 1.8.

That is, as a result of various investigations by the present inventors on various methods for producing an MQ resin without the above-mentioned disadvantages,
When the Q resin is produced by the series of steps A) to H) described above, 1) the yield per batch can be greatly increased to 4 to 5 times that of the conventional method, and 2) hydrolysis by the conventional method. Although a hydrophilic solvent was used in the process, the solvent is hardly used in the method of the present invention, and the wastewater treatment cost is unnecessary because the wastewater is exhausted.3) In the conventional method, the cohydrolyzate is washed with water. However, in the method of the present invention, the alcohol by-produced by hydrolysis, a small amount of the solvent used, and water are distilled out of the system by heating. The post-treatment can be rationalized because it is reused or incinerated. 4) Since the washing step can be omitted and the reaction speed can be accelerated, the production time of MQ resin is 1/2 to 2/2 of the conventional method. 3 can be short-circuited, 5) batches because management of each process is easy The present invention was completed by discovering that there is an advantage that the quality variation of the product can be reduced and a high quality product can be stably obtained, and research on a method for making each process more rational is completed. Let

This will be described in more detail below.

[Operation] The present invention relates to a novel method for producing an MQ resin, which is represented by the general formula [(R ¹ ₃ SiO _1/2 ) _m (SiO _4/2 ) _n ].
R ¹ is a group selected from an alkyl group, an alkenyl group, and an aryl group as described above, and m / n (molar ratio) is
It is composed of monofunctional siloxane units of 0.5 to 1.8 and tetrafunctional siloxane units.

The production of the MQ resin according to the present invention comprises steps A) to H) described above.

The hydrolysis step as the step A) is carried out by using the general formula R ¹ ₃ SiOSiR ¹ ₃ , R ¹ ₃ SiOR ² , R ¹ ₃ Si as M siloxane units in the reactor.
OH represented by at least one and / or R ¹ ₃ SiNHSiR ¹ ₃ of, R ¹ is a methyl group, an ethyl group, an alkyl group such as propyl group, a vinyl group, an allyl group, an alkenyl group such as butenyl group, a phenyl group, A monovalent hydrocarbon selected from an aryl group such as a tolyl group, R ² is an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, and preferably R ¹ ₃ SiOSiR ¹ ₃ And specifically (CH ₃ ) ₃ SiOSi
_{(CH 3) 3, (CH} 3) 2 (CH 2 = CH) SiOSi (CH = CH 2) (CH 3) 2, (CH 3) 2
C ₂ H ₅ SiOSiC ₂ H ₅ (CH ₃ ) ₂ , (C ₂ H ₅ ) ₂ CH ₃ SiOSiCH ₃ (C ₂ H ₅ ) ₂ and other organodisiloxanes, and as Q siloxane units
(R ² O) ₄ Si, for example (CH ₃ O) ₄ Si, (C ₂ H ₅ O) ₄ Si, (C ₃ H ₇ O) ₄ Si and other organosilanes or partial hydrolysis-condensation products thereof are charged. After stirring, acid and water may be added dropwise thereto to cohydrolyze these organodisiloxane and organosilane.

However, the mixing ratio of the organodisiloxane as the M siloxane unit and the organosilane as the Q siloxane unit is such that the m / n (molar ratio) in the MQ resin targeted by the present invention is 0.5 to 1.8, more preferably from the viewpoint of performance. 0.65 to 1.
Since it should be 25, it is necessary to mix it so that this m / n (molar ratio) falls within such a range. Further, in the hydrolysis of the organodisiloxane and the organosilane, a solvent that dissolves the copolymer produced by the cohydrolysis, for example, an aromatic hydrocarbon solvent such as toluene or xylene is added in advance. It is advisable to add acid and water to this. Acids used here include hydrochloric acid, sulfuric acid, phosphoric acid,
Although acetic acid may be used, hydrochloric acid does not react with the organic group bonded to the silicon atom, does not enter the siloxane bond, and has a strong action as a catalyst. Most preferred. This hydrochloric acid is diluted by water added in this hydrolysis step and alcohol by-produced in this step, but if this concentration is less than 0.3% by weight, hydrolysis, cleavage reaction and condensation reaction will be slowed down, and 20% by weight If the content exceeds%, these reactions become faster, but at the time when alcohol is not still by-produced or when the amount of by-product alcohol is small, the raw material silane which becomes the Q siloxane unit is hydrolyzed and condensed violently and is insoluble in the solvent. Since the formation of a gel-like substance occurs, the amount of hydrochloric acid added should be such that the final amount of hydrochloric acid in this system is 0.3 to 2
It is preferable to set it in the range of 0% by weight, more preferably 1 to 10% by weight. Further, the amount of water used for this hydrolysis is a sufficient amount of 1 to hydrolyze the alkoxy groups in the (R ² O ₄ ) Si and / or its partially hydrolyzed condensate to be Q siloxane units into hydroxyl groups. If the amount is less than 2 times the amount, the alkoxy groups in the raw material silane cannot be completely converted into hydroxyl groups, and the alkoxy groups will remain. If the amount exceeds 2 times, the concentration of hydrochloric acid described above becomes 1 to 10 weight of the preferable range. Therefore, the amount of hydrochloric acid to be added increases, which causes a disadvantage in the operation in the subsequent steps. Therefore, the amount should be in the range of 1/2 to 2 times the amount sufficient to hydrolyze the alkoxy groups of the raw material silane. Good.

In this hydrolysis step, as described above, the mixture of the raw material silane which becomes the M siloxane unit and the Q siloxane unit and the common solvent are charged into the hydrolysis reactor, and a predetermined amount of hydrochloric acid and water are added dropwise thereto with stirring. However, this is preferably done at a temperature of 0 to 10 ° C., which gives the advantage that gels are less likely to form. In addition, this hydrochloric acid and water may be added by dropping hydrochloric acid first, or by adding a mixture thereof, or by adding water first and then cooling the reaction system while cooling the reaction system sufficiently. However, if the molar ratio m / n of the M siloxane unit and the Q siloxane unit is small, a gel-like substance is likely to be formed at the initial stage of hydrolysis.
In this case, more than the same amount of hydrochloric acid added dropwise,
This alcohol can be prevented by dropping alcohols such as ethanol and isopropanol together with hydrochloric acid. The hydrolysis reaction is preferably carried out at a temperature as low as possible, but it may be carried out at room temperature. After completion of the reaction, this is gradually heated, and finally heated at reflux temperature for 3 to 6 hours to cause a cleavage reaction, The polycondensation reaction is preferably performed, but the end point is when the alkoxy group of the raw material silane forming the Q siloxane unit disappears.

Next, in the first neutralization step as the step B), alkali metal hydrogen carbonate is added to the reaction system after the above hydrolysis step to neutralize the acid, and then the solution is maintained at pH 3 to 6. The alkali metal hydrogencarbonate is used as an alkali for neutralizing the acid used in the hydrolysis step, especially hydrochloric acid. This is essentially any alkaline substance that neutralizes the acid, but when sodium hydrogen carbonate is used as the alkali metal hydrogen carbonate, this is less basic than alkali metal hydroxides and carbonates. It is considered to be an alkali metal hydrogencarbonate because it has a large neutralizing effect and according to this, it does not generate a gelled substance that may occur when an alkali metal hydroxide or carbonate is used. It However, even when an alkali metal hydrogencarbonate is used as the neutralizing agent, the hydrolysis reaction product still contains a large amount of active silanol groups, and this product partially dissolves when heated in the presence of an alkali catalyst. In order to prevent this and to complete the neutralization, an acid weaker than hydrochloric acid such as acetic acid is used together so that the pH of the solution is 3 to 6 after neutralization. According to this, even if sodium hydrogen carbonate and acetic acid make sodium acetate under heating in the system, they are meta-decomposed by the coexisting hydrochloric acid to become sodium chloride, and acetic acid is liberated. Is maintained at a pH of 3-6, which prevents the formation of gels. Further, this neutralization step is preferably carried out by raising the temperature by heating in order to make this as short as possible.

The first neutralization step in the present invention is carried out as described above. This is because the treatment liquid after hydrolysis in the conventional method is composed of an organic layer composed of an organic solvent and a hydrolyzate, a catalyst and water. The water layer is made into a waste liquid by separating it into a water layer, and the organic layer is washed several times with water to make the acidic liquid neutral and this washing water is also made into a waste liquid, which significantly shortens the process time. The advantage is that no waste liquid treatment is required.

After the completion of the first neutralization step, the solvent replacement step as the step C) is carried out. This solvent substitution step is for removing alcohols and residual water by-produced in the hydrolysis step from the inside of the system and keeping the desired MQ resin in a solution state. Since it has good solubility in the reaction product, aromatic hydrocarbon such as toluene, xylene, etc. may be used. The solvent replacement step is carried out at atmospheric pressure or reduced pressure in the reaction solution after the first neutralization. A method of heating below to strip alcohols, water, etc., and then stripping again by adding a target solvent, or alcohols, water, etc. are completely stripped by heating under reduced pressure from the reaction solution after the first neutralization. After that, a method of dissolving the reaction product by adding a target solvent may be used.

After the solvent replacement step, the reaction product is treated in the alkali polymerization step D), which is an important step for determining the properties of the desired MQ resin. That is, the physical properties of the MQ resin as a raw material of the silicone pressure-sensitive adhesive are the molar ratio of the M siloxane unit and the Q siloxane unit, the average molecular weight of the MQ resin, the content of the silanol group as a functional group, and the content of the residual alkoxy group. , It depends on the molecular weight distribution of the MQ resin, etc., but in order to improve the adhesive strength, it is important to minimize the content of silanol groups, make the residual alkoxy groups close to zero, and widen the molecular weight distribution as much as possible. These conditions are determined in the alkaline polymerization step.

The alkali catalyst used in this alkali polymerization step may be any one or more of alkali metal hydroxides, carbonates, and hydrogen carbonates.
In order to bring the content of silanol groups and residual alkoxy groups in the resin close to zero, it is preferable that the alkali catalyst has a strong basicity. Therefore, it is preferable to use an alkali metal hydroxide. The amount of the alkali catalyst used may be in the range of 0.01 to 3%, more preferably 0.1 to 1% with respect to the MQ resin, and the polymerization time and temperature are distilled off under reflux at the boiling point of the solution. While distilling off the condensed water, the silanol groups of the MQ resin are minimized and the residual alkoxy groups approach zero, but it is possible to shorten the time by performing at as high a temperature as possible. It is preferable to raise the concentration of the MQ resin to raise the boiling point of the solution, whereby the contents of silanol groups and residual alkoxy groups are brought close to zero,
An MQ resin having a wide molecular weight distribution can be obtained.

Next, in the acid treatment step as the step E), most of the alkali catalyst used in the alkali polymerization step is bonded to the siloxane bond in the form of siliconate, so this is decomposed,
This is to capture and return the siliconate to the original siloxane, which can be neutralized with hydrochloric acid that does not adversely affect the mineral acid, particularly the siloxane. Therefore, it is sufficient to add an amount of hydrochloric acid sufficient to neutralize the alkali used in the alkali polymerization step, for example, 1.5 times to 3 times, and treat under reflux.
1 to 15 to 35% at a temperature of 90 to 105 ℃
It suffices that the treatment is carried out for 2 hours, and according to this, the alkali is precipitated as chloride, so this can be removed.

In addition, the next F) secondary neutralization step is to remove the excess acid used in E) step, which reacts well with the hydrochloric acid used above to form a salt insoluble in the organic solvent. An alkaline substance which forms a siloxane bond or decomposes an organic group or does not combine with the siloxane bond may be used. The alkaline substance used in this step is preferably a hydroxide or carbonate of an alkaline earth metal, and therefore calcium hydroxide or calcium carbonate is preferred for this, but the amount added is The amount of hydrochloric acid used in the step should be sufficient to neutralize the excess, and in this case, too, a weak acid such as acetic acid may be used in combination to adjust the pH of the system to 3 to 6 as in step B). It is desirable to keep it.

The reaction product that has completed this secondary neutralization step is then dehydrated in the G) dehydration step. This dehydration is azeotropic, or at 10-30 ° C in the presence of a dehydrating agent such as anhydrous sodium sulfate and silica gel. It can be stirred, but this can reduce the water content to 0.001%.

This dehydrated MQ resin is finally made into a product in the H) overstep, and this overstep may be carried out by a generally known method.
According to this, the salts produced in the primary neutralization step, the acid treatment step and the secondary neutralization step and the dehydrating agent used in the dehydration step are removed, so that the desired MQ resin can be easily obtained. You can

[Examples] Next, examples of the present invention and comparative examples will be given. Parts in the examples are parts by weight.

Example 1 (Hydrolysis Step) hexamethyldisiloxane _{[(CH 3) 3 SiOSi (} CH 3) 3] 160 parts,
Charge 310 parts of methyl polysilicate having a SiO ₂ content of 51% and an average degree of polymerization of 4 and 80 parts of toluene into a four-necked flask equipped with a stirring blade, a condenser and a thermometer at 10 ° C.
While cooling and stirring, a mixture of 5 parts of 35% hydrochloric acid and 5 parts of methanol was added dropwise over 1 minute, and then 70 parts of water was added.
After dropping for 30 minutes, the temperature in the system at the end of dropping was 25 ° C, but after the dropping, it was heated to 68 ° C.
To complete the hydrolysis step.

(First Neutralization Step) The hydrolysis reaction product obtained above was cooled to 40 ° C., and toluene was added.
After adding 55 parts of the solution to a nonvolatile content of 70%, 45 parts of sodium hydrogen carbonate and 0.5 part of glacial acetic acid were added and neutralized at 68 ° C. for 2 hours. The pH of this product was 5.2.

(Solvent replacement step) Then, this was heated to 68 ° C and methanol 300 parts by-produced in the hydrolysis step, excess water, and toluene were distilled off, and 300 parts of toluene was newly added in several batches. The solvent was replaced with toluene by heating to 80 ° C., the nonvolatile content was adjusted to 80%, and then the mixture was cooled to 40 ° C.

(Alkaline polymerization step) When 2 parts of sodium hydroxide dissolved in 10 parts of methanol was added to this solution and heated, the temperature rose while distilling methanol from 70 ° C. Therefore, condensed water was refluxed at 120 ° C. Was distilled off, polymerization was carried out for 6 hours, and then toluene was added.
132 parts were added to adjust the nonvolatile content to 60%.

(Acid treatment step) Next, a mixed solution of 5.6 parts of 35% hydrochloric acid and 5.6 parts of methanol was added to this solution, and acid treatment was carried out at 95 ° C for 2 hours.
Cooled to ° C.

(Second Neutralization Step) 1 part of calcium hydroxide and 1.7 parts of glacial acetic acid were added to the solution after the acid treatment step and neutralized at 90 ° C. for 2 hours.

(Dehydration, overstep) The solution neutralized above is heated to 114 ° C to remove water by azeotropic distillation, and then cooled, and 3 parts of anhydrous sodium sulfate is added at 20 ° C to give 3
After stirring and dehydration for a long time, 503 parts of a toluene solution containing 60.2% of MQ resin was obtained. When the properties of the MQ resin thus obtained were examined, it showed the following results. .

Example 2 (hydrolysis step) hexamethyldisiloxane _{[(CH 3) 3 SiOSi (} CH 3) 3] 301 parts,
Charge 774 parts of ethyl polysilicate having an SiO ₂ content of 40% and an average degree of polymerization of 4 and 153 parts of xylene into a 2-necked four-necked flask equipped with a stirring blade, a condenser and a thermometer at 5 ° C.
The mixture was cooled to 20 ° C., 20 parts of 35% hydrochloric acid was added dropwise over 2 minutes with stirring, and then 350 parts of water was added dropwise over 1 hour.
The temperature inside the system was 30 ° C at the end of dropping.
After completion of the dropping, this was heated to 72 ° C. and stirred for 5 hours to complete the hydrolysis reaction.

(First Neutralization Step) This hydrolysis reaction product was cooled to 40 ° C, 17 parts of sodium hydrogen carbonate and 254 parts of xylene were added, and 1.5 parts of glacial acetic acid was further added and heated to neutralize at 72 ° C for 2 hours. Let

(Solvent Replacement Step) After the reaction solution after neutralization was heated to strip methanol, water, etc., 40 parts of xylene was added and heated to 144 ° C. to adjust the nonvolatile content to 60%.

(Alkaline Polymerization Step) After cooling the reaction solution to 40 ° C., 5 parts of sodium carbonate was added, the condensation water was distilled off while heating and refluxing at 144 ° C., and alkali polymerization was carried out for 5 hours. Cooled to ° C.

(Acid treatment step) After 10 parts of 35% hydrochloric acid was gradually added, the mixture was heated, subjected to acid treatment at 98 ° C for 2 hours, and then cooled to 40 ° C.

(Second Neutralization Step) 1 part of calcium hydroxide and 2 parts of glacial acetic acid were added, and the mixture was neutralized at 98 ° C. for 2 hours.

(Dehydration, over-process) 30 ° C after removing azeotropic water at 144 ° C following the previous process
After cooling, 5 parts of anhydrous sodium sulfate was added, and the mixture was stirred for 3 hours to dehydrate and then filtered, and the non-volatile content was adjusted to 60% with xylene. The resulting MQ resin in xylene had the following properties. It was as follows.

Example 3 (hydrolysis step) 148 parts of hexamethyldisiloxane, divinyltetramethyldisiloxane _{[CH 2 = CH (CH 3} ) 2 SiOSi (CH 3) 2 (CH = CH 2)] 3
Charge 6 parts, 250 parts of methyl polysilicate having a SiO ₂ content of 51% and an average degree of polymerization of 4 and 78 parts of xylene into a 1-necked four-necked flask equipped with a stirring blade, a condenser and a thermometer and cooled to 5 ° C. , 5% of 35% hydrochloric acid was added dropwise, followed by water 65
When a portion was added dropwise over 20 minutes, the temperature in the system was raised to 30 ° C., but it was further heated to cause hydrolysis at 70 ° C. for 7 hours and then cooled to 30 ° C.

(First Neutralization Step) To this hydrolysis product, 4.3 parts of sodium hydrogen carbonate, 1 part of glacial acetic acid and 130 parts of xylene were added and neutralized at 70 ° C. for 1 hour.

(Solvent Replacement Step) The reaction solution after neutralization was heated to strip methanol and water, then heated to 144 ° C., 20 parts of xylene was added to make the nonvolatile content 60%, and cooled to 50 ° C.

(Alkaline Polymerization Step) 4 parts of sodium hydrogen carbonate was added, polymerization was carried out at 143 ° C. for 5 hours, and then cooled to 40 ° C.

(Acid treatment step) 6 parts of 35% hydrochloric acid was added, and the mixture was treated with acid at 105 ° C for 2 hours and then cooled to 40 ° C.

(Second Neutralization Step) 1 part of calcium hydroxide and 1 part of glacial acetic acid were added and neutralized at 105 ° C. for 2 hours.

(Dehydration, overstep) The neutralized liquid was heated to 142 ° C to distill off azeotropic water, cooled to 30 ° C or lower, and 2 parts of anhydrous sodium sulfate was added thereto, and the mixture was stirred for 2 hours for dehydration and then passed. However, an MQ resin having the following properties was obtained.

Comparative Example 1 350 parts of water and 160 parts of toluene were charged into a 2-necked Korben equipped with a stirring blade, a condenser, and a thermometer, and cooled to 5 ° C., and 245 parts of trimethylchlorosilane and 4 parts of SiO ₂ component were added thereto.
A mixture of 450 parts of ethyl polysilicate having an average degree of polymerization of 4 at 0% and 200 parts of toluene was added dropwise over 2 hours, and the mixture was stirred at 10 to 15 ° C for 1 hour and aged. Was produced, and the molar ratio of the M siloxane unit to the Q siloxane unit was 0.75, but it could not be used as an MQ resin.

Comparative Example 2 In order to prevent the formation of a toluene-insoluble gel-like substance in Comparative Example 1, alcohol was allowed to coexist during the hydrolysis, and the four-necked Kolben 2 in Comparative Example 1 was used with 350 parts of water.
Parts, toluene 160 parts, and isopropyl alcohol 160 parts were treated and hydrolyzed in the same manner as in Comparative Example 1. No gel-like product was observed. Therefore, this was further refluxed at 78 ° C. While hydrolyzing for 2 hours, the mixture was allowed to stand and separated into a layer composed of hydrochloric acid-water-alcohol and a layer composed of MQ resin-toluene-alcohol, and MQ
Wash the resin-toluene-alcohol layer several times with hot water,
After stationary and fractionation, the alcohol content was dissolved in water and washed to neutralize the MQ resin-toluene layer.

Then, sodium carbonate was added to this MQ resin-toluene layer, the mixture was treated under reflux at 112 ° C. for 16 hours to carry out alkaline polymerization, and then the remaining sodium carbonate was separated and further boiled with ethylene chlorhydrin to give siloxane. When the sodium carbonate bound during the binding was removed and dehydration and excess were performed, MQ with the following properties was obtained.
A resin was obtained.

Reference Example A pressure-sensitive silicone adhesive was produced from the MQ resins obtained in Example 1, Example 2 and Comparative Example 2 with the same formulation, and the thickness was measured.
The thickness of the adhesive layer is 25 μm, 19 mm wide polyimide tape
A pressure-sensitive adhesive tape was prepared by coating so as to have a thickness of 35 μm.

Next, when the adhesive strength, tackiness and cohesive strength were measured by the following methods, the results as shown in Table 1 were obtained, and the adhesive tape made of the MQ resin obtained in Comparative Example 2 was obtained. The adhesive strength is 30% lower than the adhesive strength of the adhesive tapes made from the MQ resins obtained in Examples 1 and 2, and the adhesive strength is poor and the tackiness and cohesive strength are poor. It was

(Adhesive strength) The pressure-sensitive adhesive layer side of the test piece is lightly stuck to the center of the stainless steel plate (SUS27CP, 280 grit), and the thickness is about 6 mm from this.
The metal roller covered with the rubber layer and having a weight of 2,000 ± 50 g is reciprocated once at a crimping speed of 300 mm / min to crimp the test piece to the stainless steel plate. Then, this test piece is 23 ± 2 ℃,
After leaving it in a constant temperature and humidity chamber of 60 ± 5% RH for 16 hours, the play part was folded back to 180 ° and the peeling force when continuously separated at a speed of 300 mm / min was shown.

(Tackiness) Temperature 23 from the approach distance of 10 cm on a slope with an oblique angle of 30 °
JIS G 4805 SUJ2 steel balls were rolled under the conditions of ± 2 ° C and relative humidity of 60 ± 5%, and the diameter of the steel ball that stopped within the range of 10 cm of the adhesive layer was shown (tilt ball tack measurement. value).

(Cohesive force) A test piece with an area of 20 mm in length and 10 mm in width is attached to the above-mentioned stainless steel plate, a load of 1,000 ± 10 g is suspended, and 23 ± 2 ° C, 6
The deviation distance is shown after leaving for 30 minutes in an atmosphere of 0 ± 5% RH.

[Effects of the Invention] The present invention relates to a method for producing an organosilicon resin, and more particularly to a method for producing a so-called MQ resin composed of a monofunctional siloxane unit and a tetrafunctional siloxane unit, which is described above. Such as A) hydrolysis step, B) primary neutralization step, C) solvent replacement step, D) alkali polymerization step, E) acid treatment step, F) secondary neutralization step, G) dehydration step, H ) It consists of over-process, and according to this, 1) MQ compared with the conventional method.
Resin yield can be increased 4 to 5 times 1) MQ resin yield can be increased 4 to 5 times, 2) Waste water treatment is not required, 3)
The post-treatment is rationalized, 4) the manufacturing time is shortened, and 5) the quality of the product is improved, so that the desired MQ resin can be obtained easily and inexpensively on an industrial scale. Advantages are given.

Claims (1)

[Claims] 1. A) The general formula R ¹ ₃ SiOSiR ¹ ₃ , R ¹ ₃ SiO in a reactor.
At least one of R ² and R ¹ ₃ SiOH and / or R ¹ ₃ SiNHSiR
¹ ₃ (wherein R ¹ is a group selected from an alkyl group, an alkenyl group and an aryl group, R ² is an alkyl group) and a general formula (R ² O) ₄ Si (R ² is an alkyl group) ), The organosilane or its partial hydrolysis-condensation product is charged, and a hydrolysis step in which acid and water are added dropwise to hydrolyze, and B) an alkali metal hydrogen carbonate is added to the reaction system to neutralize the acid. First neutralization step of adding an acid to keep the system at pH 3 to 6, C) After removing alcohols by-produced in the hydrolysis reaction and excess water used in the hydrolysis reaction, aromatic hydrocarbons are removed. Solvent replacement step of adding a system solvent, D) an alkali polymerization step of adding at least one hydroxide and / or carbonate of an alkali metal and / or hydrogen carbonate and heating to polymerize, E) an alkali polymerization catalyst In the acid treatment step of neutralizing and removing with acid, F) acid treatment step Produced in the secondary neutralization step to remove excess acid used, G) dehydration step to remove free water in the system, H) primary neutralization step, acid treatment step, secondary neutralization step A general formula [(R ¹ ₃ SiO _1/2 ), which comprises a monofunctional siloxane unit and a tetrafunctional siloxane unit, which comprises a salt and a filtration step for removing the dehydrating agent used in the dehydration step.
_m (SiO _4/2 ) _n ] (R ¹ and R ² are the same as above), and the method for producing an organic silicon resin having m / n (molar ratio) of 0.5 to 1.8.