Polymerization of siloxane polymers

Abstract

The present disclosure provides an improved process for the preparation of high viscosity (i.e., greater than 1 million MPa.s at 25 DEG C) silanol-terminated silicone polymers and copolymers (generally referred to in the industry as silanol-terminated silicone polymer glues). The silanol-terminated silicone polymer glue is prepared by ring opening polymerization of an organocyclosiloxane oligomer (or called cyclic silicone oligomer) using a conical screw tablet press (1). The invention also relates to a silanol-terminated silicone polymer gel prepared by the method.

Description

[0001] The present invention relates to an improved process for preparing high viscosity (i.e., greater than 1 million MPa.s at 25°C) silanol-terminated organosilicon polymers and copolymers (commonly referred to in the industry as silanol-terminated organosilicon polymer gums). The silanol-terminated organosilicon polymer gums are prepared by ring-opening polymerization of organocyclosiloxane oligomers (or cyclic organosilicon oligomers). The present invention also relates to silanol-terminated organosilicon polymer gums prepared by the process.

[0002] Organocyclosiloxane oligomers are formed by the hydrolysis of diorganodichlorosilanes and can be isolated by distillation. They are key intermediates in the silicone industry as they can be used as main building blocks in the preparation of silicone polymers and copolymers and their corresponding gums.

[0003] Each siloxane unit in an organocyclosiloxane generally has the structure

[0004] -[(R′2)SiO]-

[0005] wherein each R' group is identical or different and is selected from an alkyl group, an alkenyl group, an aryl group, a fluoroalkyl group such as a trifluoropropyl group or a perfluoroalkyl group. Thus, the organocyclosiloxane oligomer may, for example, contain dimethylsiloxane units, methylvinylsiloxane units, trifluoroalkylmethylsiloxane units, for example trifluoropropylmethylsiloxane units and / or phenylmethylsiloxane units in the ring.

[0006] The organocyclosiloxane oligomers preferably used as polymer structural units typically have an average of 3 to 5 siloxane units in the organocyclosiloxane ring. Examples of suitable organocyclosiloxane oligomers are octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, decamethylcyclopentasiloxane, cyclopenta(methylvinyl)siloxane, cyclotetra(phenylmethyl)siloxane, cyclopentamethylhydrogensiloxane, trifluoropropylmethylcyclotrisiloxane, and mixtures thereof.

[0007] Typically, organocyclosiloxane oligomers and mixtures thereof (alone or with appropriately end-capped polydiorganosiloxanes) undergo a polymerization process involving ring opening of the organocyclosiloxane oligomers in the presence of a catalyst such as an acid or base. During the polymerization reaction, an equilibrium is created between the desired polymer compound and the mixture of the organocyclosiloxane compound. The resulting equilibrium depends primarily on the nature and amount of the organocyclosiloxane compound, the catalyst used, and the polymerization process temperature. Such polymerization processes are typically carried out in the absence of a solvent. Typically, end-capping agents are used to increase functionality and to adjust the molecular weight of the resulting polymer.

[0008] For example, silicone polymers and copolymers containing fluoroalkyl groups (such as trifluoropropyl groups) or perfluoroalkyl groups may be, for example:

[0009] R 1 (R 2 )2SiO-((R 4 )(R 3 )SiO) m -Si(R 1 )(R 2 )(I)

[0010] R 1 (R 2 )2SiO-((R 4 )(R 3 )SiO) m -((R 2 )2SiO) q Si(R 1 )(R 2 )2(II)

[0011] in

[0012] Each R 2 are the same or different and are saturated monovalent hydrocarbon groups such as alkyl groups, aryl groups or alkaryl groups, fluoroalkyl groups or perfluoroalkyl groups;

[0013] Each R 1 is -OH, hydrogen, an alkenyl group, or an alkynyl group;

[0014] Each R 3 is a fluoroalkyl group or a perfluoroalkyl group;

[0015] Each R 4 YesR 2 or an unsaturated monovalent hydrocarbon group, such as an alkenyl group or an alkynyl group; and

[0016] q and m are positive integers. The copolymer may be a random or block copolymer.

[0017] Such organosilicon polymers and / or organosilicon copolymers are typically prepared via a ring-opening polymerization process starting from an organocyclosiloxane (including fluorine-substituted organocyclosiloxanes such as tris(fluoropropylmethyl)tricyclosiloxane: ((CH3)(CH2CH2CF3)SiO)3) and a suitable catalyst such as an alkali metal hydroxide, an alkali metal alkoxide, or a complex of an alkali metal hydroxide and an alcohol; a silanolate such as an alkali metal silanolate, a phosphazene halide (sometimes referred to as an acidic phosphazene), a phosphazene base, and a catalyst derived by reacting a tetraalkylammonium hydroxide and a siloxane tetramer, as described in US 3,433,765.

[0018] The viscosity of the resulting polymer can be controlled / limited using suitable chain initiators / end-capping agents such as water or suitable short-chain siloxanes such as short-chain silanols. After the polymerization is complete, the catalyst is quenched in a suitable manner and the remaining low-molecular components can be stripped off if necessary.

[0019] Batch processes for preparing silicone polymer glues using the above-mentioned ring-opening polymerization methods often use a kneader-type mixer to prepare the silicone polymer glue, and then transfer / dump the resulting polymer into a second piece of equipment (such as a disc or large hopper extruder) for down-packaging. However, transferring polymer materials between equipment can lead to contamination and reliability issues, which have led to the need for, for example, polytetrafluoroethylene (PTFE) filling and laborious cleaning steps because of the need to dump and scrape residual materials between batches due to conversion losses. In addition, the need to transfer polymers between separate equipment provides the possibility of exposing operators to potentially toxic materials.

[0020] Provided herein is a method for producing a silanol-terminated silicone polymer adhesive, wherein the silanol-terminated silicone polymer adhesive has a William plasticity of at least 200 mm / 100 according to ASTM D-926-08; the method comprising: performing a ring-opening polymerization of one or more organocyclosiloxane oligomers, the organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule, the siloxane units comprising dialkylsiloxane units, alkylalkenylsiloxane units, trifluoroalkylalkylsiloxane units, perfluoroalkylalkylsiloxane units, phenylalkylalkylsiloxane units, or mixtures thereof in the organocyclosiloxane ring, wherein each alkyl group is the same or different and contains 1 to 10 carbons, and each alkenyl group is the same or different and has 2 to 10 carbons; by:

[0021] (i) delivering the one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule to a polymerization reactor heated to a predefined temperature of 40° C. to 170° C. in an inert atmosphere,

[0022] (ii) simultaneously with or after step (i), introducing a suitable chain initiator / end-capping agent of an -OH-containing substance into the polymerization reactor and mixing the chain initiator / end-capping agent of an -OH-containing substance with the organocyclosiloxane oligomer while removing residual water if necessary,

[0023] (iii) introducing a catalyst suitable for catalyzing the ring-opening polymerization into the polymerization reactor to form a reaction mixture with the resulting mixture of step (ii), and then performing a ring-opening polymerization of the one or more organocyclosiloxane oligomers to produce an organosilicon polymer gum reaction product;

[0024] (iv) quenching the organosilicon polymer glue reaction product obtained from step (iii), and optionally vacuum stripping the organosilicon polymer glue reaction product in the polymerization reactor using a vacuum device;

[0025] (v) cooling the organosilicon polymer adhesive reaction product produced by step (iv) to form a final organosilicon polymer adhesive reaction product, and then performing either step (vi) or step (vii) or both steps (vi) and (vii);

[0026] (vi) transporting the final silicone polymer adhesive reaction product to a packaging device for packaging in a suitable storage container;

[0027] (vii) transporting the final silicone polymer adhesive reaction product to a compounding device to mix the silicone polymer adhesive reaction product with other ingredients;

[0028] Characterized in that the polymerization reactor utilized is a conical screw dump extruder comprising a conical twin-screw chamber accommodating two counter-rotating conical screws converging toward an extrusion die having an inlet and an outlet, wherein the passage through the extrusion die is controlled by a plugging device so that the outlet of the extrusion die is adapted to be closed by the plugging device until the end of step (v) and to be opened during step (vi), step (vii), or both steps (vi) and (vii), so that during polymerization the reaction mixture is driven toward the extrusion die by the pair of counter-rotating conical screws and then forced back when the extrusion die is closed by the plugging device, and then during step (vi), step (vii), or both steps (vi) and (vii), the reaction mixture is extruded through the extrusion die and conveyed to the packaging device and / or the compounding device, respectively.

[0029] Also provided is a silanol-terminated organic silicone polymer glue obtained or obtainable by the above method, wherein the silanol-terminated organic silicone polymer glue has a William plasticity of at least 200 mm / 100 according to ASTM D-926-08.

[0030] The present invention also provides the use of a conical screw tablet press as a polymerization reactor in the production process of a silanol-terminated silicone polymer glue, wherein the silanol-terminated silicone polymer glue has a William plasticity of at least 200 mm / 100 according to ASTM D-926-08; the method comprises: performing a ring-opening polymerization of one or more organocyclosiloxane oligomers, the organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule, the siloxane units comprising dialkylsiloxane units, alkylalkenylsiloxane units, trifluoroalkylalkylsiloxane units, perfluoroalkylalkylsiloxane units, and phenylalkylalkylsiloxane units or mixtures thereof in the organocyclosiloxane ring, wherein each alkyl group is the same or different and contains 1 to 10 carbons, and each alkenyl group is the same or different and has 2 to 10 carbons; the method is:

[0031] (i) delivering the one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule to a polymerization reactor heated to a predefined temperature of 40° C. to 170° C. in an inert atmosphere;

[0032] (ii) simultaneously with or after step (i), introducing a suitable chain initiator / end-capping agent of an -OH-containing substance into the polymerization reactor, and mixing the chain initiator / end-capping agent of an -OH-containing substance with the organocyclosiloxane oligomer, while removing residual water if necessary;

[0033] (iii) introducing a catalyst suitable for catalyzing the ring-opening polymerization into the polymerization reactor to form a reaction mixture with the resulting mixture of step (ii), and then performing a ring-opening polymerization of the one or more organocyclosiloxane oligomers to produce an organosilicon polymer gum reaction product;

[0034] (iv) quenching the organosilicon polymer glue reaction product obtained from step (iii), and optionally vacuum stripping the organosilicon polymer glue reaction product in the polymerization reactor using a vacuum device;

[0035] (v) cooling the organosilicon polymer adhesive reaction product produced by step (iv) to form a final organosilicon polymer adhesive reaction product; and then performing either step (vi) or step (vii) or both steps (vi) and (vii);

[0036] (vi) transporting the final silicone polymer adhesive reaction product to a packaging device for packaging in a suitable storage container;

[0037] (vii) transporting the final silicone polymer adhesive reaction product to a compounding device to mix the silicone polymer adhesive reaction product with other ingredients;

[0038] Characterized in that the polymerization reactor utilized is a conical screw tablet press comprising a conical twin-screw chamber accommodating two counter-rotating conical screws converging toward an extrusion die having an inlet and an outlet, wherein the passage through the extrusion die is controlled by a blocking device so that the outlet of the extrusion die is adapted to be closed by the blocking device until the end of step (v) and to be opened during step (vi), step (vii), or both steps (vi) and (vii), so that during polymerization the reaction mixture is driven toward the extrusion die by the pair of counter-rotating conical screws and then forced back when the extrusion die is closed by the blocking device, and then during step (vi), step (vii), or both steps (vi) and (vii), the reaction mixture is extruded through the extrusion die and conveyed to the packaging device and / or the compounding device, respectively.

[0039] It should be understood that the present disclosure relates to a polymerization process starting from a low viscosity organocyclosiloxane oligomer and not compounding many ingredients to prepare a silicone base composition or a curable composition. The conical screw tablet press is designed to mix preformed polymers and fillers into the base material or use the low viscosity organocyclosiloxane oligomer as the initial ingredient to be compounded with other ingredients not used for polymerization.

[0040] The one or more organocyclosiloxane oligomers have 3 to 5 siloxane units per molecule, including dialkylsiloxane units, alkylalkenylsiloxane units, trifluoroalkylalkylsiloxane units, perfluoroalkylalkylsiloxane units, phenylalkylalkylsiloxane units, or mixtures thereof in the organocyclosiloxane ring,

[0041] Wherein each alkyl group is the same or different and contains 1 to 10 carbons, or is the same or different and contains 2 to 10 carbons. Any suitable organocyclosiloxane oligomer having 3 to 5 siloxane units per molecule or combination of organocyclosiloxane oligomers can be used in the methods herein. Each siloxane unit in the organocyclosiloxane oligomer generally has the following structure

[0042] -[(R′2)SiO]-

[0043] Wherein each R' group is the same or different and is selected from an alkyl group, an alkenyl group, an aryl group, a fluoroalkyl group such as a trifluoropropyl group or a perfluoroalkyl group. Examples of suitable organocyclosiloxane oligomers include, but are not limited to, octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, decamethylcyclopentasiloxane, penta(methylvinyl)cyclopentasiloxane, tetra(phenylmethyl)cyclotetrasiloxane, penta(methylhydrogen)cyclopentasiloxane, tri(methylvinyl)cyclotrisiloxane, tri(ethylvinyl)cyclotrisiloxane, tetra(methylvinyl)cyclotetrasiloxane, tetra(ethylvinyl)cyclotetrasiloxane, penta(methylvinyl)cyclopentasiloxane and penta(ethylvinyl)cyclopentasiloxane.

[0044] The organocyclosiloxane oligomer used in this method can contain fluorine-containing groups, including fluoroalkyl groups such as trifluoropropyl, trifluoroethyl and nonafluorohexyl groups), and perfluoroalkyl groups such as, for example, CF3-, C2F5-, C3F7- such as CF3CF2CF2- or (CF3)2CF-, C4F9- such as CF3CF2CF2CF2-, (CF3)2CFCF2-, (CF3)3C- and CF3CF2(CF3)CF-; C5F 11 Such as CF3CF2CF2CF2CF2-, C6F 13 -, such as CF3(CF2)4CF2-; C7F 14 -, such as CF3(CF2CF2)3-; and C8F 17 -.

[0045] Specific examples include tris(fluoropropylmethyl)tricyclosiloxane, tris(fluoropropylethyl)tricyclosiloxane, tetrakis(fluoropropylmethyl)tetracyclosiloxane, tetrakis(fluoropropylethyl)tetracyclosiloxane, penta(fluoropropylmethyl)pentacyclosiloxane, penta(fluoropropylethyl)pentacyclosiloxane, tris(fluoroethylmethyl)tricyclosiloxane, tris(fluoroethylethyl)tricyclosiloxane, tetrakis(fluoroethylmethyl)tetracyclosiloxane, tetrakis(fluoroethylethyl)tetracyclosiloxane, penta(fluoroethylmethyl)pentacyclosiloxane, penta(fluoroethylethyl)pentacyclosiloxane, and mixtures thereof.

[0046] Any suitable chain initiator / capping agent containing -OH species may be used to initiate polymerization and / or terminate / cap the resulting silicone polymer gum.

[0047] These-OH substances can be water, alcohol, glycol. Specific examples include straight or branched aliphatic alcohols with 2 to 10 carbons per molecule, including ethanol, propanol, butanol, amyl alcohol, hexanol, heptanol, octanol, isopropanol, isobutanol, 2-methyl-1-butanol and 3-methyl-1-butanol, propylene glycol, ethylene glycol and / or butanediol. Alternatively,-OH substances can be short-chain organopolysiloxanes, which have at least one-OH group per molecule, such as disilanol or trisilanol, and a degree of polymerization of 2 to 30, comprising any suitable siloxane units, such as (Me2Si-O) units, (ViMeSi-O) units, (MePHSi-O) units, (Ph2Si-O) units and (MeTFPSi-O) (wherein TFP represents trifluoropropyl) or mixtures thereof. The short chain organopolysiloxane having at least one -OH group per molecule has an average degree of polymerization of 2 to 30 per molecule, alternatively an average degree of polymerization of 3 to 25, including an average degree of polymerization of 5 to 25. As a specific example, the chain initiator / capping agent containing the -OH species may be

[0048] HO(MeTFPSi-O) d -H

[0049] wherein the average value of d is an average degree of polymerization of 2 to 30 per molecule, or an average degree of polymerization of 2 to 25, or an average degree of polymerization of 2 to 20 inclusive, or an average degree of polymerization of 2 to 15 inclusive, or an average degree of polymerization of 2 to 10 inclusive, wherein Me represents methyl and TFP represents trifluoropropyl.

[0050] The catalyst used herein can be any catalyst suitable for catalyzing ring-opening polymerization, for example:

[0051] (I) a suitable base catalyst, for example a suitable hydroxide, such as potassium hydroxide, cesium hydroxide or ammonium hydroxide or a silanolate;

[0052] (II) a suitable alkali metal alkyl, such as n-butyllithium, n-butylsodium and n-butylpotassium;

[0053] (III) ammonia;

[0054] (IV) a complex of an alkali metal alkoxide or an alkali metal hydroxide with an alcohol;

[0055] (V) catalysts derived by reaction of tetraalkylammonium hydroxide and siloxane tetramer as described in US 3433765;

[0056] (VI) Alkali metal-containing silanolates, for example potassium silanolate such as potassium trimethylsilanolate ((CH3)3-Si-O - K +), lithium silanolate and sodium silanolate such as sodium trifluoropropylmethylsilanolate having the following structure:

[0057]

[0058] wherein when added to the starting organocyclosiloxane oligomer, the initial average value of n is between 3 and 6;

[0059] (VII) Non-metallic silanolates, such as

[0060] Silanolates of alkylammonium hydroxide compounds, such as tetramethylammonium trimethylsilanol [(CH3)4N-OSi(CH3)3], tetraethylammonium trimethylsilanol, tetrapropylammonium trimethylsilanol, tetramethylammonium triethylsilanol, tetraethylammonium triethylsilanol, tetrapropylammonium triethylsilanol, tetramethylammonium tripropylsilanol, tetraethylammonium tripropylsilanol, and tetrapropylammonium tripropylsilanol;

[0061] (VIII) Phosphazene bases. Many phosphazene bases and their synthetic routes have been described in the literature; and

[0062] (IX) Transient silanolate catalysts such as trifluoropropylmethylammonium silanolate.

[0063] Typically, for such catalysts, except for instantaneous catalysts (IX), the activity of the catalyst is quenched by using a neutralizing agent, which reacts with the catalyst to make the catalyst inactive after the polymerization reaction is completed. Any suitable neutralizing agent can be utilized. These can include, for example, weak acids, such as weak Lewis acids that can effectively neutralize alkaline catalysts. Such neutralizing agents can be selected from, for example, phosphoric acid, tris(chloroethyl)phosphite silyl phosphate, carbon dioxide, and suitable buffers such as NaH2PO4 or Na2HPO4. Available alternative neutralizing agents are weak Lewis acid carbon dioxide, which works when used in combination with silanol catalysts. For example, when the catalyst used is sodium silanol, the neutralizing agent will typically react with sodium silanol to form sodium bicarbonate end groups and other sodium salts. Other neutralizing agents such as silylphosphonates and pyrogenic silica can be utilized alone or in combination with silanols. The selection of neutralizing agent can allow the stripping of the glue product to be improved by improving the thermal stability of the glue.

[0064] In the case of transient catalyst (IX), the polymerization reactor is heated / cooled to a reaction temperature of 40°C to 60°C in an inert atmosphere to allow the polymerization reaction to occur, and then subsequently, instead of introducing a neutralizing agent, the reaction mixture is quenched by heating the final product to a temperature of at least 80°C after the polymerization process is complete to generate ammonia gas, which is then removed from the polymerization reactor under vacuum. This can have the advantage that the use of a vacuum can help strip out at least some of the residual organocyclosiloxane and byproducts of the polymerization reaction in the conical screw tablet press polymerization reactor using heat and vacuum.

[0065] The starting ingredients for the polymerization reactions used herein will contain greater than (>) 99.5% of the organocyclosiloxane oligomer along with sufficient levels of silanolate catalyst and chain initiator / capping agent of -OH containing species.

[0066] The silanol-terminated silicone polymer gums prepared by the methods herein are typically linear or substantially linear, meaning that they contain less than 2.5 wt.% branching, alternatively less than 1.5 wt.% branching, alternatively less than 0.5 wt.% branching, alternatively less than 0.1 wt.% branching. According to ASTM D-926-08, the William plasticity of the silanol-terminated silicone polymer gums prepared by the methods herein is at least 200 mm / 100. Silicone polymer gums (also referred to in the industry as organopolysiloxane polymer gums, silicone polymer gums, or siloxane gums) have very high viscosities (at least 1,000,000 mPa.s at 25°C, often millions of MPa.s at 25°C). Due to the difficulty in measuring the viscosity of such highly viscous fluids, silicone polymer gums tend to be defined by their Williams plasticity (the ability of a specimen to compress under an external force and to maintain the deformation after the external force is removed) rather than by viscosity. Typically, in the case of fluorosilicone polymer gums measured according to ASTM D-926-08, the Williams plasticity value of the silicone polymer gum may be up to about 400 mm / 100. Alternatively, the Williams plasticity of the silanol-terminated silicone polymer gum prepared by the method herein is at least 225 mm / 100 according to ASTM D-926-08, alternatively 250 mm / 100 according to ASTM D-926-08. Such plasticity values ​​ensure that the resulting polymer product can be extruded from the polymerization reactor without leaving traces of unextruded material in the conical screw tablet press, which must be removed between batches.

[0067] In the method of this article, the following steps are provided:

[0068] (i) delivering the one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule to a polymerization reactor heated to a predefined temperature of 40° C. to 170° C. in an inert atmosphere;

[0069] (ii) simultaneously with or after step (i), introducing a suitable chain initiator / end-capping agent of an -OH-containing substance into the polymerization reactor, and mixing the chain initiator / end-capping agent of an -OH-containing substance with the organocyclosiloxane oligomer, while removing residual water if necessary;

[0070] (iii) introducing a catalyst suitable for catalyzing the ring-opening polymerization into the polymerization reactor to form a reaction mixture with the resulting mixture of step (ii), and then performing a ring-opening polymerization of the one or more organocyclosiloxane oligomers to produce an organosilicon polymer gum reaction product;

[0071] (iv) quenching the organosilicon polymer glue reaction product obtained from step (iii), and optionally vacuum stripping the organosilicon polymer glue reaction product in the polymerization reactor using a vacuum device;

[0072] (v) cooling the organosilicon polymer adhesive reaction product produced by step (iv) to form a final organosilicon polymer adhesive reaction product; and then performing either step (vi) or step (vii) or both steps (vi) and (vii);

[0073] (vi) transporting the final silicone polymer adhesive reaction product to a packaging device for packaging in a suitable storage container;

[0074] (vii) transporting the final silicone polymer adhesive reaction product to a compounding device to mix the silicone polymer adhesive reaction product with other ingredients;

[0075] Before use, the selected organocyclosiloxane oligomer is stored in a suitable storage container or directly supplied from manufacturing. If the selected organocyclosiloxane oligomer is supplied to a storage container directly stored from manufacturing for immediate use or supplied to the storage container for immediate use, or if the selected organocyclosiloxane oligomer is directly supplied from manufacturing, the optional removal of residual water is optional and may be unnecessary, because there will be almost no water to be removed. However, if the selected organocyclosiloxane oligomer is stored in a suitable storage container for several days or longer, the removal of residual water will be necessary. In the step (i) of the method, the selected organocyclosiloxane oligomer starting material is, for example, transported (e.g., pumped) from a storage container or directly transported to a polymerization reactor from manufacturing. The polymerization reactor is a conical screw tablet press, such as described in US7556419 and US2021113975 from Colmec SpA for compounding pre-prepared ingredients to prepare a base composition or a curable silicone-based composition. The organocyclosiloxane oligomer is introduced into the conical screw tablet press through the entrance into the mixing chamber. If an oligomer stream is supplied to the polymerization reactor, the oligomer stream can be directly transferred. In the case of using two or more organocyclosiloxane oligomer streams, if necessary, these organocyclosiloxane oligomer streams can be pre-mixed in a suitable mixer before entering the polymerization reactor so that different organocyclosiloxane oligomers are fully mixed with each other when introduced into the polymerization reactor. When more than one organocyclosiloxane oligomer is utilized, the corresponding organocyclosiloxane oligomers can be introduced into the conical screw tablet press simultaneously or by any other suitable mixing scheme, such as having an organocyclosiloxane oligomer at the beginning of the process, and periodically introducing an aliquot of a second organocyclosiloxane oligomer during the silanol-terminated organosilicon polymer glue production method.

[0076] When in liquid form, the organocyclosiloxane oligomer used herein has a low viscosity, for example <100 mPa.s at 25°C. The conical screw tablet press is not designed for mixing the low viscosity organocyclosiloxane oligomer as a main ingredient or actually used as a polymerization reactor. The conical screw tablet press is designed to mix preformed polymers and fillers into a base material or to use the low viscosity organocyclosiloxane oligomer as an initial ingredient to mix with other ingredients not used for polymerization.

[0077] As described above, during step (i) of the method, the polymerization reactor is heated to a predefined temperature of 40°C to 170°C in an inert atmosphere. The selected initial elevated temperature is selected to remove excess water by evaporation in step (ii) after adding a suitable chain initiator / capping agent containing -OH substances. However, excess water may be additionally or alternatively extracted with the aid of online molecular sieve traps, which may be installed in pipelines to remove water when the components are pumped through these online molecular sieve traps. When evaporation is relied upon to remove excess water in step (ii), the predefined temperature selected in step (i) is typically 100°C to 170°C. The inert atmosphere may be any suitable inert atmosphere, but is typically a nitrogen atmosphere. The introduction of a suitable -OH species for use as a chain initiator / end-capping agent into the polymerization reactor in step (ii) of the process may be carried out before, simultaneously with or after step (i), and the resulting combination of one or more organocyclosiloxane oligomers and one or more chain initiators / end-capping agents is mixed and heated to a predetermined temperature of 100° C. to 170° C., while removing residual water if necessary, as described above.

[0078] Once the residual water has been removed, in step (iii), if necessary, a basic catalyst suitable for catalyzing the ring-opening polymerization is introduced into the polymerization reactor, thereby enabling the ring-opening polymerization to start, followed by polymerization to produce the silicone polymer gum. The predefined temperature selected in step (i) may be the preferred polymerization temperature for step (iii) after the catalyst has been introduced. Typically, in the case of catalyst types (I) to (VIII), the preferred polymerization temperature is between 100°C and 170°C, inclusive. However, if the predefined temperature in step (i) is different from the preferred polymerization temperature for step (iii), the mixture obtained from step (ii) may be heated or cooled before the catalyst is added.

[0079] In the case of an instantaneous catalyst (IX), the desired reaction temperature is 40°C to 60°C in an inert atmosphere. Thus, when an instantaneous catalyst is chosen and water is driven off by heating in step (ii), the polymerization reactor is cooled to a temperature of 40°C to 60°C in an inert atmosphere for the polymerization reaction prior to the introduction of the catalyst, and then subsequently, instead of introducing a neutralizing agent in step (iv) to quench the reaction, the reaction mixture may be heated to at least 80°C at the end of the polymerization process to generate ammonia gas, which is then removed from the polymerization reactor under vacuum. This may have the advantage that the use of a vacuum may help to strip out at least some of the residual organocyclosiloxane and byproducts of the polymerization reaction using heat and vacuum in the conical screw tablet press polymerization reactor.

[0080] As previously mentioned, the polymerization reactor is a conical screw tablet press including a conical twin-screw chamber that accommodates two counter-rotating conical screws that converge toward an extrusion die. In use, the starting ingredients for the polymerization reaction and the product in the polymerization reactor are driven toward the extrusion die by the counter-rotating screws. However, when the shut-off device is closed, the starting ingredients and / or the polymerized product are forced to return upward to the conical twin-screw chamber for further recirculation / additional mixing, thereby enhancing the uniformity of the polymerized product during polymerization. The two counter-rotating screws are in a converging and intersecting conical channel, wherein the peripheral profile of the screw threads extends adjacent to the channel surface. Therefore, during the silanol-terminated silicone polymer glue production method, as the reactants and polymerized product approach the closed extrusion die, the material is forced to follow the conical profile of the screw to a gradually narrowing volume, thereby increasing the pressure.

[0081] This pressure increase makes it possible to recirculate the contents of the reaction chamber. If necessary, for example, when the polymer has reached a very high viscosity (such as a hard gel), the rotation of the two screws can also be temporarily reversed to help the polymerization and / or mixing process. Polytetrafluoroethylene (PTFE) fillers can be used. However, in one embodiment, if necessary, the screw can include a lip seal on the shaft of the screw.

[0082] The extrusion die has an inlet and an outlet, wherein the passage from the inlet to the outlet in the polymerization reactor through the extrusion die is controlled by the above-mentioned blocking device. The blocking device is maintained in a closed position during the silanol-terminated silicone polymer gum production method (e.g., steps (i) to (v) above), thereby preventing the discharge of any contents present in the polymerization reactor (conical screw tablet press), so that the contents in the reactor (e.g., starting ingredients, polymer and any by-products) are driven toward the extrusion die by a pair of counter-rotating screws and then forced back into the conical reaction chamber for further repeated mixing for a predefined polymerization reaction period.

[0083] In step (iv), the reaction is quenched. In most cases, this is achieved by introducing a suitable neutralizing agent as described above into the polymerization reactor to neutralize the mixture produced by the silanol-terminated organosilicon polymer gum production process, in particular the organosilicon polymer gum produced by step (iii). In some cases, when necessary, a vacuum may be applied inside the polymerization reactor to vacuum strip the quenched products of step (iii) and step (iv), for example to remove any residual organocyclosiloxane oligomers and / or impurities and / or by-products.

[0084] In step (v) of the method, the resulting polymer product is cooled to a predefined temperature between 30°C and 80°C, alternatively between 30°C and 70°C, and then once cooled, the closure device is moved to an open position to allow the resulting silicone polymer glue product to be extruded through an extrusion die.

[0085] In step (vi), the silicone polymer glue product flowing out of the polymerization reactor through the extrusion die is collected and transferred to a suitable packaging device, or can be pumped to a packaging device if it has an acceptable viscosity. In step (vii), the silicone polymer glue product flowing out of the polymerization reactor through the extrusion die is transported to a compounding device for further processing, i.e., mixed with additional ingredients to prepare, for example, a gel product, a rubber matrix or a curable rubber compound, etc., which is mixed with other ingredients after mixing with a suitable reinforcing filler or a suitable curable silicone rubber composition, the filler, a crosslinking agent (if necessary) and a catalyst or a curing agent to prepare, for example, a silicone rubber matrix. The compounding device can be any suitable compounding machine type mixer, such as a sigma blade kneader mixer, a bottom discharge kneader mixer, a conical twin-screw mixer (e.g., a screw tablet press), a planetary extruder, a co-kneader extruder, a twin-screw extruder, a single screw extruder and / or a twin-roll mill, but in this case in a preferred embodiment it can be a second conical screw tablet press. In this case, if desired, the silanol-terminated silicone polymer glue product can first undergo a reaction to replace the silanol end groups with alternative end groups (e.g., unsaturated end groups, such as alkenyl end groups or alkynyl end groups, typically alkenyl end groups such as vinyl end groups). Alternatively, the polymer glue can be terminated with trialkyl end groups. When end-capping is performed, this is performed by maintaining the newly polymerized silanol glue at a temperature of 20° C. to 70° C., and then adding small molecules such as silanes or disilazanes (such as divinyltetramethyldisilazane or hexamethyldisilazane) under continuous mixing. The silazane is then reacted with the -OH end groups on the reaction product to "end-cap" the reaction product. The temperature can then be raised to between 100° C. and 190° C. to remove any residual by-products such as ammonia. If desired or otherwise required, a vacuum can also be optionally applied. As described above, previous batch processes for preparing silicone polymer glues using the above-mentioned ring-opening polymerization process often use a kneader-type mixer to prepare the silicone polymer glue (high viscosity silicone polymers with a viscosity greater than 1,000,000 mPa.s at 25°C) and then transfer / pour the resulting polymer into a second piece of equipment such as a disk or large hopper extruder for subsequent packaging. One advantage of utilizing a conical screw tablet press as a polymerization reactor as described herein is that it eliminates many of the aforementioned problems because there is no need to transfer polymer material between equipment. Use of a conical screw tablet press allows mixing and dispensing to the packaging device from the same piece of equipment, and thereby contamination and reliability issues can be avoided.

[0086] Furthermore, utilizing a conical screw tablet press as a polymerization reactor in this process avoids the previously laborious cleaning steps between batches, since the need to dump and scrape residual material between batches due to conversion losses is avoided, and the need to transfer polymer between equipment is avoided, which protects the operator from exposure to any potentially toxic materials. This is because the conical screw tablet press is effectively self-cleaning. The combination of the conical shape of the screw and the shape of the inner surface of the mixing body allows for complete unloading of the batch. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] The present disclosure is further explained below with reference to the accompanying drawings, in which:

[0088] Figure 1 A schematic depiction showing an example of a method for producing a silanol terminated silicone polymer gum as described herein.

[0089] exist Figure 1 In the invention, a conical screw tablet press (1) is provided, which is used as a polymerization reactor for the ring-opening polymerization of organocyclosiloxane oligomers. The conical screw tablet press (1) has a conical twin-screw chamber (1a) which accommodates two intermeshing conical screws (not shown) which converge to an extrusion die (2). A plate-shaped blocking device (3) is also provided, which can be moved between an open position and a closed position, so that in the closed position the blocking device (3) is designed to prevent the polymer product from flowing out during the silanol-terminated organosilicon polymer glue production method, and in the open position (not shown) allows the polymer product to flow out through the extrusion die. The two intermeshing conical screws are operated in a counter-rotating manner and are driven by a motor (14) of the conical screw tablet press (1). If necessary, the intermeshing conical screws can include lip seals on the shaft.

[0090] Figure 1 Also depicted are two organocyclosiloxane oligomer storage tanks (4) and (5) and corresponding delivery lines (6) and (7) for transferring the corresponding organocyclosiloxane oligomers to the conical screw dump extruder (1) through entry ports (8) and (9). In the illustrated embodiment, two entry ports (8) and (9) are provided for introducing the organocyclosiloxane oligomers into the conical screw tablet press (1). If desired, these can be replaced by using an organocyclosiloxane oligomer hopper (not shown) instead of entry ports (8) and (9) to supply the organocyclosiloxane oligomers to the conical screw tablet press (1). Alternatively or additionally, if desired, the delivery lines can be directed to a mixing device, such as a static mixer, to mix the organocyclosiloxane oligomers together before entering the conical screw tablet press (1).

[0091] A neutralizer supply tank (10), a neutralizer delivery line (11), and a neutralizer inlet port (12) are also provided. A catalyst supply tank (15), a catalyst delivery line (16), and a catalyst inlet port (17) are also provided. A chain initiator / capping agent supply tank (20), a chain initiator / capping agent delivery line (21), and a chain initiator / capping agent inlet port (22) are also provided.

[0092] Once the silicone polymer gel prepared in the conical screw tablet press (1) has flowed out through the extrusion die (2), it can be transported to the packaging device (30) for packaging and storage.

[0093] In use, any number of different organocyclosiloxane oligomers may be utilized, but typically one organocyclosiloxane oligomer or a mixture of 2, 3, 4 or 5 different organocyclosiloxane oligomers will be utilized, more often 1, 2 or 3 organocyclosiloxane oligomers and frequently 1 or 2 organocyclosiloxane oligomers. For the purposes of this figure, there are two selected organocyclosiloxane oligomers and they are supplied from organocyclosiloxane oligomer storage tanks (4) and (5) via respective delivery lines (6) and (7) and through respective inlet ports (8) and (9) to a conical screw tablet press (1). For example, when preparing a fluorosilicone polymer / copolymer gum, the organocyclosiloxane oligomer supplied to the conical screw tablet press (1) may be (3,3,3-trifluoropropyl)methylcyclotrisiloxane: ((CH3)(CH2CH2CF3)SiO)3 alone or in combination with one or more other organocyclosiloxane oligomers such as octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, tri(methylvinyl)cyclotrisiloxane, tri(ethylvinyl)cyclotrisiloxane, tetra(methylvinyl)cyclotetrasiloxane or tetra(ethylvinyl)cyclotetrasiloxane. For the sake of example, we will describe the process below based on the organocyclosiloxane oligomers present being tri(fluoropropylmethyl)tricyclosiloxane and optionally tri(methylvinyl)cyclotrisiloxane. Therefore, for the benefit of this specification, if / when required, (3,3,3-trifluoropropyl)methylcyclotrisiloxane is supplied to the conical screw tablet press (1) from the organocyclosiloxane oligomer storage tank (4), and tri(methylvinyl)cyclotrisiloxane is supplied to the conical screw tablet press (1) from the organocyclosiloxane oligomer storage tank (5). They can be supplied in any order, simultaneously, or indeed can be supplied premixed if required. The starting ingredients for polymerization are maintained in an inert atmosphere, typically in a nitrogen atmosphere. Typically, the conical screw tablet press (1) can be purged with nitrogen before the introduction of the organocyclosiloxane oligomer.

[0094] Simultaneously or after the organocyclosiloxane oligomer is introduced into the conical screw tablet press (1), an initiator / capping agent is supplied to the conical screw tablet press (1) from a supply tank (20) via a chain initiator / capping agent delivery line (21) and through the chain initiator / capping agent inlet port (22), and then mixed with the organocyclosiloxane oligomer using two intermeshing conical screws of the conical screw tablet press (1). The occluding device (3) is in a closed position. The resulting mixture is heated to a predefined temperature between 40°C and 170°C, typically between 100°C and 170°C, thereby allowing any excess water to be driven off. The initiator / capping agent can, for example, be any of the above-mentioned initiators / capping agents, but for this embodiment is a silanol having the following structure

[0095] HO-(MeTFPSi-O) d -H

[0096] The average value of d is 4 to 8.

[0097] Once the excess water has been driven off / evaporated and the mixture in the conical screw tablet press (1) has reached a predefined reaction temperature of 40°C to 170°C, depending on the catalyst to be used for the polymerization reaction, the catalyst is introduced from the catalyst supply tank (15) via the catalyst delivery line (16) through the catalyst inlet port (17) into the conical screw tablet press (1). The catalyst can be any suitable catalyst as described above, but in this case, it is preferably, for example, a suitable silanolate, for example an alkali metal silanolate, a non-metallic silanolate, such as ammonium silanolate; or an alkali metal hydroxide. In the examples herein, a suitable alkali metal silanolate is used as the catalyst.

[0098] The polymeric ingredients are then continuously mixed using the two intermeshing conical screws of the conical screw tablet press (1) with the closure device (3) in the closed position for a predetermined period of time, which depends on the desired polymer product.

[0099] During the process for producing a silanol-terminated silicone polymer gum, the contents of a conical screw tablet press (1) (i.e., polymeric ingredients) and the resulting polymer or gum are continuously mixed using two counter-rotating intermeshing conical screws, such that during polymerization, the contents are driven by the pair of counter-rotating screws toward an extrusion die (2) and then forced upward back into the conical twin screw chamber (1a) into the conical screw tablet press (1). This continues for the entire period of time while being prevented from exiting through the extrusion die (2) by a blocking device (3) in a closed position.

[0100] If desired, a sample of the polymer produced via the ring-opening polymerisation process in the conical screw tablet press (1) can be taken and analysed to check that the viscosity or, in the case of a gel, the Williams plasticity is within a predefined acceptable range after the stopper (3) has been opened and before the polymer sample is discharged from the conical screw tablet press (1) through the extrusion die (2).

[0101] Once the polymerization reaction has been completed (i.e., by undergoing the reaction for a predefined specific length of time) or has reached a predefined physical property value (e.g., a predefined Williams plasticity value), the polymerization reaction can be quenched, for example, by introducing a suitable neutralizing agent, typically a weak Lewis acid, as previously described. The neutralizing agent is transferred from the neutralizing agent supply tank (10) and through the neutralizing agent delivery line (11) and enters the conical screw tablet press (1) via the neutralizing agent entry port (12). The neutralizing agent can, for example, be carbon dioxide. Subsequently, any residual starting components and / or by-products produced during the silanol-terminated silicone polymer glue production method herein can be extracted by vacuum and / or can be vacuum stripped.

[0102] After the optional vacuum extraction step or vacuum stripping step is completed, the polymer product obtained in the conical screw tablet press (1) is cooled, and then the blocking device (3) is moved to the open position, thereby enabling the silicone polymer gum product to be extruded from the conical screw tablet press (1) through the extrusion die (2) and transferred to (here Figure 1 In the case of ( ) packaging device (30) for packaging / storage.

[0103] According to ASTM D-926-08, the William plasticity of the silanol-terminated silicone polymer gum prepared by the method herein is at least 200 mm / 100. Alternatively, the William plasticity of the silanol-terminated silicone polymer gum prepared by the method herein is at least 225 mm / 100 according to ASTM D-926-08, and alternatively at least 250 mm / 100 according to ASTM D-926-08.

[0104] The method for producing silanol-terminated silicone polymer glues described herein utilizing a conical screw tablet press (1) as a polymerization reactor (rather than as a compounding device as previously identified) provides several advantages over previous polymerization reactors previously used. For example, the use of a conical screw tablet press (1) enables the resulting polymer / glue to be mixed and transferred to a packaging device from the same piece of equipment because the conical screw tablet press (1) serves as both a reactor and an extruder, because in this case the resulting silicone polymer glue product can be extruded through the extrusion die (2) once the closure device (3) is in the open position, thereby enabling the polymer to be directly conveyed to the packaging device (30). This single piece of equipment utilization gives the following additional advantages: its use results in a reduced risk of contamination and reliability issues.

[0105] Furthermore, typically conical screw tablet presses (1), such as those commercially available from Colmec SpA of Busto Arsizio, Italy, have a clamshell opening design, which enables easy cleaning during use as a polymerization reactor (if desired). It has also been determined that very little or no pouring and scraping is required between preparation of polymer batches due to the small loss of total batch weight remaining in the mixer after extrusion (heel). This also has the advantage of reducing the labor intensity of the process and further limiting the risk of operator exposure to ingredients and by-products involved in the polymerization process described herein.

[0106] Additionally, the conical screw tablet press may have integrated vacuum system capabilities that may enable stripping of the organosilicon polymer product to reduce the level of residual starting materials and / or by-products. Example

[0107] A series of examples are provided below to show the applicability of this method for preparing silanol-terminated silicone polymer glues having a William plasticity of at least 200 mm / 100 according to ASTM D-926-08. All glues prepared and / or used in the following examples contain at least one silanol end group. All plasticity targets and actual measurements given in the following table are William plasticity values ​​according to ASTM D-926-08. The reaction times provided describe the length of time utilized in the examples to prepare the glue from the starting materials. The batch size is the approximate volume of the starting ingredients in the conical screw tablet press used in the examples. In the table, TFP is intended to mean trifluoropropyl.

[0108] In Ex.1-1, using Colmec TMThe CTM-65 mixer is used as a conical screw tablet press (1) to prepare a silanol-terminated silicone polymer glue according to the production method of a silanol-terminated silicone polymer glue. The organic cyclosiloxane oligomer used is trifluoropropylmethylsiloxane trimer and a small amount of vinylmethylsiloxane trimer. The chain initiator / capping agent containing -OH substance is a silanol having the following structure:

[0109] HO(MeTFPSi-O) d -H

[0110] Wherein the average value of d is between 4 and 8, and the catalyst is a silanolate. Each component is introduced into a conical screw tablet press as described herein. The final volume of the starting ingredients is about 5 liters, wherein greater than (>) 99.5% of the mixture is one or more organocyclosiloxane oligomers and a sufficient level of silanolate catalyst. The ring-opening polymerization step is carried out at a temperature of about 130°C for a period of about 60 minutes, and then the reaction / catalyst is quenched using solid carbon dioxide. Until the neutralizing agent is added, the closure device (3) in the conical screw tablet press (1) is maintained in a closed position. Subsequently, the closure device (3) is opened to allow the resulting prepared silanol-terminated silicone polymer glue to be extruded through an extrusion die (2) and then transported for packaging. The resulting silanol-terminated silicone polymer gum having a William plasticity greater than 200 mm / 100 produced in the conical screw tablet press (1) was found to mix well and extruded cleanly through the extrusion die (2), with approximately 0.1 wt. % of the total batch weight remaining in the mixer after extrusion (sometimes referred to as 0.1 wt. % tail).

[0111] In the case of Example Ex. 1.2, a previously prepared fluorosilicone polymer gum was inserted into a conical screw tablet press (1), mixed for a short time with the stopper (3) closed, and then extruded through an extrusion die (2) once the stopper was opened to determine whether the gum extruded well. It was found that gums with a Williams plasticity greater than 200 mm / 100 were well mixed and extruded cleanly through the extrusion die (2), with less than (<) 1.5 wt.% of the total batch weight remaining in the mixer after extrusion.

[0112] In the case of Ex. 1-3, a similar process to Ex. 1-1 was carried out to produce a silanol terminated silicone polymer gum having a lower William plasticity value. The organocyclosiloxane oligomer used was only trifluoropropylmethylsiloxane trimer. It was found that the process worked and the silanol terminated silicone polymer gum was well mixed and cleanly extruded through the extrusion die (2), with 1.5 wt.% of the total batch weight remaining in the mixer after extrusion.

[0113] The results and details are summarized in Table 1a.

[0114] Table 1a: In Colmec TM Silanol-terminated silicone polymer gel prepared and / or mixed in CTM-65 mixer Details

[0115]

[0116] The actual plasticity of the rubber product can be finely tuned by controlling the chain initiator / capping agent level and / or the catalyst level.

[0117] Two comparative examples were then evaluated. Comparative Example 1 was prepared and tested for extrudability and TM The mixing in the CTM-65 mixer, while Comparative Example 2 is another pre-made gum, which has a much lower Williams plasticity result compared to the above Examples 1-1 to 1-3. This is achieved by introducing a higher loading of the capping agent into the mixer.

[0118] In the case of Comparative Example 1, Colmec TM CTM-65 mixer was used to prepare the glue. In this case, a plasticity below 200 mm / 100 was intentionally polymerized in a manner similar to Example 1-1. However, in this case, the resulting glue had a much lower plasticity target and actual reading. The resulting glue was found to be unsuitable for use in Colmec TM CTM-65 mixer, because the resulting gum was very viscous in the conical twin screw chamber (1a), and only 42 wt.% of the silanol-terminated silicone polymer gum was found from Colmec TM CTM-65 mixer extrusion, leaving 58 wt.% in the extruder, which in fact requires a laborious cleaning regimen before the next batch can be prepared. This is considered unsatisfactory and it is therefore considered that materials with this William plasticity are not suitable for use in Colmec TM The CTM-65 mixer could not be polymerized satisfactorily because the material could not be extruded satisfactorily, requiring a significant and time-consuming cleaning regimen between batches.

[0119] Comparative Example 2 is a second pre-prepared resulting silanol terminated silicone polymer gum. In this case it was prepared from dimethylsiloxane trimer as the starting organocyclosiloxane oligomer. The pre-prepared gum was inserted into a conical screw tablet press (1), mixed for a short time with the closure device (3) closed, and then extruded through the extrusion die (2) once the closure device (3) had been opened to determine whether the gum extruded well. It was found that gum with a William plasticity below 200 mm / 100 mixed well, but only about 65 wt.% of the gum was successfully extruded through the extrusion die (2), leaving 35 wt.% in the extruder, which resulted in the fact that a laborious cleaning regimen was required before the next batch could be prepared. This was considered unsatisfactory and it was therefore considered that materials with such William plasticity were not suitable for use in Colmec.TM The CTM-65 mixer could not be polymerized satisfactorily because the material could not be extruded satisfactorily, requiring a significant and time-consuming cleaning regimen between batches.

[0120] These results are summarized in Table 1.b below.

[0121] Table 1b:

[0122] Comparative Example 1 Comparative Example 2 Glue Type 100% TFP-Me silicone glue 100% dimethyl silicone rubber Reaction time 60min N / A Batch size (L) 5 5 Plasticity target (4.5mL, 3min) 190.5mm / 100 177.8mm / 100 Actual value of plasticity 190.0mm / 100 181.9mm / 100

Claims

1. A method for producing a silanol-terminated silicone polymer adhesive, wherein the silanol-terminated silicone polymer adhesive has a William plasticity of at least 200 mm / 100 according to ASTM D-926-08; include: Conducting a ring-opening polymerization of one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule, said siloxane units comprising dialkylsiloxane units, alkylalkenylsiloxane units, trifluoroalkylalkylsiloxane units, perfluoroalkylalkylsiloxane units, phenylalkylalkylsiloxane units, or mixtures thereof in the organocyclosiloxane ring, wherein each alkyl group is the same or different and contains 1 to 10 carbons and each alkenyl group is the same or different and has 2 to 10 carbons; by: (i) delivering the one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule to a polymerization reactor heated to a predefined temperature of 40° C. to 170° C. in an inert atmosphere, (ii) simultaneously with or after step (i), introducing a suitable chain initiator / end-capping agent of an -OH-containing substance into the polymerization reactor and mixing the chain initiator / end-capping agent of an -OH-containing substance with the organocyclosiloxane oligomer while removing residual water if necessary, (iii) introducing a catalyst suitable for catalyzing the ring-opening polymerization into the polymerization reactor to form a reaction mixture with the resulting mixture of step (ii), and then performing a ring-opening polymerization of the at least one organocyclosiloxane oligomer to produce an organosilicon polymer gum reaction product; (iv) quenching the organosilicon polymer glue reaction product obtained from step (iii), and optionally vacuum stripping the organosilicon polymer glue reaction product in the polymerization reactor using a vacuum device; (v) cooling the organic silicone polymer glue reaction product produced by step (iv) to form a final organic silicone polymer glue reaction product; and then performing either step (vi) or step (vii) or both steps (vi) and (vii) (vi) transporting the final silicone polymer adhesive reaction product to a packaging device (30) for packaging in a suitable storage container; (vii) conveying the final silicone polymer adhesive reaction product to a compounding device to mix the silicone polymer adhesive reaction product with other ingredients; Characterized in that the polymerization reactor utilized is a conical screw tablet press (1) comprising a conical twin-screw chamber (1a), wherein the conical twin-screw chamber (1a) accommodates two counter-rotating conical screws converging toward an extrusion die (2) having an inlet and an outlet, wherein the passage through the extrusion die (2) is controlled by a blocking device (3), so that the outlet of the extrusion die (2) is adapted to be closed by the blocking device (3) until the end of step (v), and in step (vi), step (vii), or step (vi) and step (vii) i) is opened during both steps, so that during polymerization, the reaction mixture is driven by the pair of counter-rotating conical screws toward the extrusion die (2), and then when the extrusion die (2) is closed by the blocking device (3), the reaction mixture is forced back into the conical twin-screw chamber (1a), and then during step (vi), step (vii), or both steps (vi) and (vii), the reaction mixture is extruded through the extrusion die (2) and conveyed to the packaging device (30) and / or the compounding device, respectively. 2 . The method for producing a silanol-terminated organic silicone polymer glue according to claim 1 , wherein each of the organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule is a cyclic trimer.

3. A method for producing a silanol-terminated silicone polymer gum according to any preceding claim, wherein the organocyclosiloxane oligomer comprises alkylvinylsiloxane units and / or trifluoropropylmethylsiloxane units.

4. The method for producing a silanol-terminated organic silicone polymer adhesive according to any preceding claim, wherein the organic cyclosiloxane oligomer comprises octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, decamethylcyclopentasiloxane, penta(methylvinyl)cyclopentasiloxane, tetra(phenylmethyl)cyclotetrasiloxane, penta(methylhydrogen)cyclopentasiloxane, tri(methylvinyl)cyclotrisiloxane, tri(ethylvinyl)cyclotrisiloxane, tetra(methylvinyl)cyclotetrasiloxane, tetra(ethylvinyl)cyclotetrasiloxane, penta(methylvinyl)cyclopentasiloxane, penta(methylhydrogen)cyclopentasiloxane, tri(methylvinyl)cyclotrisiloxane, tri(ethylvinyl)cyclotrisiloxane, tetra(methylvinyl)cyclotetrasiloxane, tetra(ethylvinyl)cyclotetrasiloxane, penta(methylvinyl)cyclopentasiloxane, penta(methylhydrogen)cyclopentasiloxane [0063] The invention also includes but is not limited to cyclopentasiloxane, cyclopentasiloxane, tris(fluoropropylmethyl)tricyclosiloxane, tris(fluoropropylethyl)tricyclosiloxane, tetra(fluoropropylmethyl)tetracyclosiloxane, tetra(fluoropropylethyl)tetracyclosiloxane, penta(fluoropropylmethyl)pentacyclosiloxane, penta(fluoropropylethyl)pentacyclosiloxane, tris(fluoroethylmethyl)tricyclosiloxane, tris(fluoroethylethyl)tricyclosiloxane, tetra(fluoroethylmethyl)tetracyclosiloxane, tetra(fluoroethylethyl)tetracyclosiloxane, penta(fluoroethylmethyl)pentacyclosiloxane, penta(fluoroethylethyl)pentacyclosiloxane and mixtures thereof.

5. A method for producing a silanol-terminated organosilicon polymer gum according to any preceding claim, wherein the catalyst is a silanolate catalyst.

6. A method for producing a silanol-terminated organosilicon polymer gum according to any preceding claim, wherein the catalyst is an alkali metal-containing silanolate catalyst.

7. The method for producing a silanol-terminated organosilicon polymer gum according to any preceding claim, wherein the quenching of step (iv) is carried out by introducing a neutralizing agent.

8. The method for producing a silanol-terminated organic silicone polymer adhesive according to claim 7, wherein the neutralizing agent comprises phosphoric acid, tris(chloroethyl)phosphite silyl phosphate, carbon dioxide, NaH 2 PO 4 、Na 2 HPO 4 , silylphosphonates and / or fumed silica.

9. The method for producing a silanol-terminated organic silicon polymer glue according to any one of claims 1 to 6, wherein the catalyst is a transient silanolate catalyst.

10. The method for producing a silanol-terminated organosilicon polymer gum according to any preceding claim, wherein in step (i), the selected organocyclosiloxane oligomer is delivered from a suitable storage tank (4, 5) or supplied directly from manufacture.

11. The method for producing a silanol-terminated silicone polymer gum according to any preceding claim, wherein the compounding device of step (vii) is a second conical screw tablet press.

12. A silanol terminated silicone polymer gum obtained or obtainable by a process according to any preceding claim, having a Williams plasticity of at least 200 mm / 100 according to ASTM D-926-08.

13. The silanol-terminated silicone polymer gum according to claim 12, wherein the Williams plasticity of the silanol-terminated silicone polymer gum is at least 225 mm / 100 according to ASTM D-926-08.

14. The silanol terminated organosilicon polymer gum according to claim 12 or 13, which is linear or substantially linear with less than 2.5 wt.% branching.

15. Use of a conical screw tablet press (1) as a polymerization reactor in the production of a silanol-terminated organosilicon polymer glue, wherein the silanol-terminated organosilicon polymer glue has a William plasticity of at least 200 mm / 100 according to ASTM D-926-08; the method include: Conducting a ring-opening polymerization of one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule, said siloxane units comprising dialkylsiloxane units, alkylalkenylsiloxane units, trifluoroalkylalkylsiloxane units, perfluoroalkylalkylsiloxane units, and phenylalkylalkylsiloxane units or mixtures thereof in said organocyclosiloxane ring, wherein each alkyl group is the same or different and contains 1 to 10 carbons and each alkenyl group is the same or different and has 2 to 10 carbons; by: (i) delivering the one or more organocyclosiloxane oligomers having 3 to 5 siloxane units per molecule to a polymerization reactor heated to a predefined temperature of 40° C. to 170° C. in an inert atmosphere, (ii) simultaneously with or after step (i), introducing a suitable chain initiator / end-capping agent of an -OH-containing substance into the polymerization reactor and mixing the chain initiator / end-capping agent of an -OH-containing substance with the organocyclosiloxane oligomer while removing residual water if necessary, (iii) introducing a catalyst suitable for catalyzing the ring-opening polymerization into the polymerization reactor to form a reaction mixture with the resulting mixture of step (ii), and then performing a ring-opening polymerization of the one or more organocyclosiloxane oligomers to produce an organosilicon polymer gum reaction product; (iv) quenching the organosilicon polymer glue reaction product obtained from step (iii), and optionally vacuum stripping the organosilicon polymer glue reaction product in the polymerization reactor using a vacuum device; (v) cooling the organosilicon polymer glue reaction product produced by step (iv) to form a final organosilicon polymer glue reaction product; and then performing either step (vi) or step (vii) or both steps (vi) and (vii); (vi) transporting the final silicone polymer adhesive reaction product to a packaging device (30) for packaging in a suitable storage container; (vii) conveying the final silicone polymer adhesive reaction product to a compounding device to mix the silicone polymer adhesive reaction product with other ingredients; The polymerization reactor used is a conical screw tablet press (1) comprising a conical twin-screw chamber (1a), wherein the conical twin-screw chamber (1a) contains two counter-rotating conical screws converging toward an extrusion die (2) having an inlet and an outlet, wherein the passage through the extrusion die (2) is controlled by a blocking device (3), so that the outlet of the extrusion die (2) is adapted to be closed by the blocking device (3) until the end of step (v), and in step (vi), step (vii), or step (vi) and step (v) ii) opened during both, so that during polymerization, the reaction mixture is driven by the pair of counter-rotating conical screws toward the extrusion die (2), and then when the extrusion die (2) is closed by the blocking device (3), the reaction mixture is forced back into the conical twin-screw chamber (1a), and then during step (vi), step (vii), or both steps (vi) and (vii), the reaction mixture is extruded through the extrusion die (2) and conveyed to the packaging device (30) and / or the compounding device, respectively.

Images