Method for producing polycarbonate copolymer and polycarbonate copolymer

Abstract

This invention provides a novel method for producing polycarbonate copolymers. [Solution] A method for producing a polycarbonate copolymer comprises a decomposition step in which raw materials containing a polycarbonate resin and a polyester resin or polyurethane resin are heated and stirred in a reaction apparatus to obtain decomposition products, and a drying step in which the decomposition products are dried. For each resin contained in the raw materials, if the resin is amorphous, Tg + 50°C is used as the reference temperature, and if the resin is crystalline, the melting point of the resin is used as the reference temperature. The heating temperature in the decomposition step is at or above the highest reference temperature among the resins contained in the raw materials, and furthermore, at least one of the following conditions [A] and condition [B] is satisfied. Condition [A]: The raw material further comprises a polyhydric alcohol having 2 to 6 OH groups. Condition [B]: In the decomposition process (step S1), (mass of water in the reaction apparatus) / (mass of raw materials) is 1.0 to 10.0%.

Description

[Technical Field]

[0001] This invention relates to a method for producing polycarbonate copolymers and to polycarbonate copolymers themselves. [Background technology]

[0002] Conventionally, a method for producing a polycarbonate copolymer is known, which involves mixing polycarbonate with a thermoplastic resin such as polyester and reacting them in the presence of a catalyst.

[0003] Japanese Patent Publication No. 9-216492 discloses a method for producing a degradable copolymer obtained by heating and dehydrating aromatic polycarbonate and aliphatic polyester in the presence of a catalyst. The publication lists as specific examples of catalysts "metals of groups II, III, IV, and V of the periodic table, their oxides or salts," "organometallic oxides of the above metals," "metallic alkoxides of the above metals," and "alkyl metals of the above metals."

[0004] Japanese Patent Publication No. 2016-516879 discloses a method for producing a block material comprising aliphatic polycarbonate chains bonded to hydrocarbons. The production method disclosed in the said publication comprises the step of copolymerizing one or more epoxides with CO2 in the presence of a chain transfer agent, the chain transfer agent being a hydrocarbon moiety having one functional group that can act as a polymerization initiator for copolymerization of the epoxide and CO2.

[0005] Japanese Patent Publication No. 4840887 discloses a method for producing a block copolymer containing polycarbonate. In this method, (A) the constituent units in the polymer are polycarbonate and other different polymer components, and the other different polymer components are selected from the group consisting of polyamide, polyester, and polyarylate, (B) a phosphite ester compound and (C) a metal phosphite salt and / or a metal hypophosphite salt are mixed and melt-kneaded to obtain a block copolymer, and then an acidic stabilizer selected from phosphorus compounds and carboxylic acids is added.

[0006] Japanese Patent Publication No. 63-215718 discloses a method for producing polyester / polycarbonate copolymers. The publication describes a method for obtaining copolymers by reacting a mixture of high molecular weight poly(alkylene arylate) and high molecular weight polycarbonate selected from poly(divalent phenol carbonate) or poly(divalent phenol arylate / carbonate) in a predetermined ratio in a molten state at a temperature of 245°C to 315°C for 0.1 to 40 minutes in the presence of a basic catalyst. Examples of basic catalysts include alkaline earth metal oxides, alkyl esters of titanate, and salts of arylphosphinic acid.

[0007] Japanese Patent Publication No. 5-295094 discloses a method for producing polycarbonate ester block copolymers. This method involves reacting a high molecular weight polycarbonate (A') with an intrinsic viscosity of 0.5 or higher with a high molecular weight polyester (B') with an intrinsic viscosity of 0.5 or higher in the presence of a transesterification catalyst to produce a polycarbonate ester block copolymer, and then adding a phosphorus compound sufficient to deactivate the catalyst. The publication states that titanium or tin catalysts may be used as the transesterification catalyst.

[0008] Japanese Patent Publication No. 2011-74342 discloses a resin composition containing polycarbonate (A) and a block copolymer (B) having polycarbonate structural units (I) and polyester structural units (II). The publication describes a method for producing the block copolymer (B) by melting and stirring polycarbonate (A') and polyester (C) at 220-280°C and carrying out a transesterification reaction under reduced pressure. Compounds such as Na, Sn, Ti, Zr, Zn, Ge, Co, Fe, Al, Mn, and Hf are listed as transesterification catalysts to be used in this process. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 9-216492 [Patent Document 2] Special Publication No. 2016-516879 [Patent Document 3] Patent No. 4840887 [Patent Document 4] Japanese Patent Application Publication No. 63-215718 [Patent Document 5] Japanese Patent Application Publication No. 5-295094 [Patent Document 6] Japanese Patent Publication No. 2011-74342 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The methods described in the above-mentioned literature all involve obtaining polycarbonate copolymers using a catalyst that promotes polymerization between polycarbonate and other resins. However, when such polymerization-promoting catalysts are used, the molecular weight of the resulting polycarbonate copolymer tends to be high. Depending on the application, a high molecular weight of the polycarbonate copolymer may be undesirable. Furthermore, if the catalyst contains metal, metal components may remain as impurities in the resulting polycarbonate copolymer. Depending on the application, the presence of metal components in the polycarbonate copolymer may be undesirable.

[0011] The object of the present invention is to provide a novel method for producing polycarbonate copolymers and to provide novel polycarbonate copolymers. [Means for solving the problem]

[0012] A method for producing a polycarbonate copolymer according to an embodiment of the present invention includes a decomposition step of heating and stirring a raw material containing a polycarbonate resin and a polyester resin or a polyurethane resin in a reaction apparatus to obtain decomposition products, and a drying step of drying the decomposition products. For each resin contained in the raw material, when the resin is an amorphous resin, the temperature of the glass transition temperature of the resin + 50°C is used as the reference temperature of the resin, and when the resin is a crystalline resin, the melting point of the resin is used as the reference temperature of the resin. The heating temperature in the decomposition step is not less than the highest temperature among the reference temperatures of the resins contained in the raw material, and further satisfies at least one of the following conditions [A] and condition [B]. Condition [A]: The raw material further contains a polyhydric alcohol having 2 to 6 OH groups. Condition [B]: In the decomposition step, (the mass of water in the reaction apparatus) / (the mass of the raw material) is 1.0 to 10.0%.

[0013] A polycarbonate copolymer according to an embodiment of the present invention includes a structural unit derived from a polycarbonate resin, a structural unit derived from a polyester resin or a polyurethane resin, and a structural unit derived from a polyhydric alcohol having 2 to 6 OH groups.

Advantages of the Invention

[0014] According to the present invention, a polycarbonate copolymer can be produced by a method different from the conventional method.

Brief Description of the Drawings

[0015] [Figure 1] FIG. 1 is a flowchart of a method for producing a polycarbonate copolymer according to an embodiment of the present invention. [[ID=2b将“ [Figure 2] ”翻译为“ [Figure 2] ”,以此类推。5]] [Figure 2] FIG. 2 is a diagram schematically showing the screw arrangement of an extruder used in the examples.

Modes for Carrying Out the Invention

[0016] The present inventors investigated a method for producing polycarbonate copolymers using a method different from conventionally known methods that use catalysts.

[0017] As a result, we found that by heating and stirring raw materials containing polycarbonate resin and polyester resin or polyurethane resin in an environment with a predetermined amount of moisture, the decomposition and bonding of these resins proceed simultaneously, and a copolymer of polycarbonate resin can be obtained without the use of a catalyst.

[0018] The inventors further discovered that by including a polyhydric alcohol having 2 to 6 OH groups in the raw material, the decomposition of the raw material resin is promoted, and a copolymer of polycarbonate resin can be obtained even with a very low water content.

[0019] The present invention was completed based on these findings. Embodiments of the present invention will be described in detail below with reference to the drawings.

[0020] <Method for producing polycarbonate copolymer> Figure 1 is a flow chart of a method for producing a polycarbonate copolymer according to one embodiment of the present invention. This production method comprises a decomposition step (step S1) and a drying step (step S2).

[0021] [Disassembly process] The decomposition step (step S1) is a step in which raw materials containing polycarbonate resin (hereinafter sometimes referred to as "first resin") and polyester resin or polyurethane resin (hereinafter sometimes referred to as "second resin") are heated and stirred in a reaction apparatus to obtain decomposition products.

[0022] The reaction apparatus should be capable of stirring the raw materials while they are heated. Preferably, the reaction apparatus should be capable of controlling the atmosphere inside. Specifically, it is preferable that the reaction apparatus has a structure that allows the inside to be sealed, except for the raw material inlet and outlet, gas inlet and outlet (vent), water inlet, etc. The reaction apparatus is preferably made of metal, glass, or ceramic, and is particularly preferably made of metal. The reaction apparatus may be a batch type or a continuous type, but a continuous type is preferred. It is particularly preferable that the reaction apparatus is an extruder capable of continuously processing the raw materials while heating and kneading them. A more preferred configuration when using an extruder will be described later.

[0023] The raw materials may contain substances other than the first resin and the second resin. For example, the raw materials may contain polyhydric alcohols as described later. The raw materials may also further contain a thermoplastic resin different from both the first resin and the second resin. In this case, the "thermoplastic resin different from both the first resin and the second resin" is preferably a different type of polyester resin or polyurethane resin than the second resin. Hereinafter, "total amount of resin contained in the raw materials" means the total amount of all resins contained in the raw materials (the amount obtained by removing components other than resin from the raw materials).

[0024] [First type of resin (polycarbonate resin)] The first resin (polycarbonate resin) may be an aliphatic polycarbonate or an aromatic polycarbonate. The first resin is preferably an aromatic polycarbonate, and is particularly preferably one synthesized from 2,2-bis(4-hydroxyphenylpropane).

[0025] The proportion of the first resin (polycarbonate resin) in the raw materials is preferably 10 to 90% by mass of the total amount of resin in the raw materials. The lower limit of the proportion of the first resin in the raw materials is more preferably 30% by mass. The upper limit of the proportion of the first resin in the raw materials is more preferably 70% by mass.

[0026] [Second resin (polyester resin or polyurethane resin)] The second resin is a polyester resin or a polyurethane resin. Examples of polyester resins, though not limited to these, include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene adipate naphthalate, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polyhydroxybutyric acid, polyhydroxyalkanoate, polyglycolic acid, 3-hydroxybutyrate-co-3-hydroxyhexanoate, and among these, polybutylene succinate and polybutylene terephthalate are preferred. Examples of polyurethane resins, though not limited to these, include polyester-based polyurethanes and polyether-based polyurethanes.

[0027] The proportion of the second resin (polyester resin or polyurethane resin) in the raw material is preferably 10 to 90% by mass of the total amount of resin in the raw material. The lower limit of the proportion of the second resin in the raw material is more preferably 30% by mass. The upper limit of the proportion of the second resin in the raw material is more preferably 70% by mass.

[0028] The ratio of the first resin to the second resin is not limited to this, but the ratio of the mass of the first resin to the mass of the second resin may be 10:90 to 90:10. Preferably, the ratio of the mass of the first resin to the mass of the second resin is 30:70 to 70:30. By keeping the ratio within this range, the properties (physical properties) of the two types of resin can be exhibited.

[0029] The second resin is preferably a polyester resin. In other words, the raw material preferably contains a polyester resin.

[0030] Each of the resins contained in the raw materials (the first resin, the second resin, and any other resins added as needed) preferably has a number average molecular weight of 5,000 or more, and more preferably 15,000 or more. Each of the resins contained in the raw materials also preferably has a weight average molecular weight of 10,000 or more, and more preferably 30,000 or more.

[0031] [Polyhydric alcohols] The raw material may further contain a polyhydric alcohol having 2 to 6 OH groups (hereinafter sometimes simply referred to as "polyhydric alcohol"). Examples of polyhydric alcohols having 2 to 6 OH groups include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, 2-methyl-2,3-butanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, 2-butyne-1,4-diol, polyethylene glycol, trimethylolpropane, glycerin, erythritol, pentaerythritol, glucose, etc. Polyhydric alcohols with a valency of 3 or higher are preferred, and trimethylolpropane and pentaerythritol are particularly preferred.

[0032] The amount of polyhydric alcohol is preferably 0.1 to 10.0 parts by mass per 100 parts by mass of the total amount of resin contained in the raw material. If the amount of polyhydric alcohol is too small, the effect described later (the effect of promoting the decomposition of the resin contained in the raw material) may not be sufficiently obtained. If the amount of polyhydric alcohol is too large, the polycarbonate copolymer may gel. The lower limit of the amount of polyhydric alcohol is preferably 0.5 parts by mass, and more preferably 0.8 parts by mass, per 100 parts by mass of the total amount of resin contained in the raw material. The upper limit of the amount of polyhydric alcohol is preferably 5.0 parts by mass, and more preferably 3.0 parts by mass, per 100 parts by mass of the total amount of resin contained in the raw material.

[0033] In one embodiment, the raw material may mainly consist of a first resin and a second resin. In this case, the amount of components other than the first resin and the second resin contained in the raw material is preferably 10% by mass or less of the total raw material, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0034] In another embodiment, the raw material may mainly consist of three or more resins, including a first resin and a second resin. In this case, the amount of components other than resins contained in the raw material is preferably 10% by mass or less of the total raw material, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0035] In another embodiment, the raw material may mainly consist of a first resin, a second resin, and a polyhydric alcohol. In this case, the amount of components other than the first resin, the second resin, and the polyhydric alcohol contained in the raw material is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0036] In yet another embodiment, the raw material may mainly consist of three or more resins, including a first resin and a second resin, and a polyhydric alcohol. In this case, the amount of components other than resins and polyhydric alcohols contained in the raw material is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1% by mass or less.

[0037] In any of the above cases, it is preferable that the raw material contains as little as possible metals of Groups II, III, IV, and V of the periodic table, their oxides or salts, organometallic oxides of the above metals, metal alkoxides of the above metals, alkyl metals of the above metals, and metal phosphite and metal hypophosphite salts. The total amount of metals of Groups II, III, IV, and V of the periodic table, their oxides or salts, organometallic oxides of the above metals, metal alkoxides of the above metals, alkyl metals of the above metals, and metal phosphite and metal hypophosphite salts contained in the raw material is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and it is even more preferable that these are substantially absent.

[0038] [Heating temperature, etc.] For each resin contained in the raw materials, if the resin is amorphous, the "reference temperature" of the resin is set to the glass transition temperature of the resin + 50°C, and if the resin is crystalline, the "reference temperature" of the resin is set to the melting point of the resin. In this case, the heating temperature in the decomposition process (step S1) shall be at or above the highest reference temperature among the resins contained in the raw materials. For example, if polycarbonate (amorphous resin) with a glass transition temperature of 150°C is used as the first resin and polybutylene succinate (crystalline resin) with a melting point of 120°C is used as the second resin, the heating temperature in the decomposition process (step S1) shall be 200°C or higher. Also, if polycarbonate (amorphous resin) with a glass transition temperature of 150°C is used as the first resin and polybutylene terephthalate (crystalline resin) with a melting point of 230°C is used as the second resin, the heating temperature in the decomposition process (step S1) shall be 230°C or higher. If the raw materials include a resin with a higher standard temperature than the first and second resins, the heating temperature should be set to a temperature equal to or higher than the standard temperature of that resin.

[0039] The higher the heating temperature during the decomposition step (step S1) (hereinafter referred to as the "decomposition temperature"), the more easily the reaction proceeds. The lower limit of the decomposition temperature is preferably 250°C, more preferably 260°C, and even more preferably 280°C. On the other hand, if the decomposition temperature is too high, bonds other than carbonate ester bonds and ester bonds may break. The upper limit of the decomposition temperature is preferably 340°C, and even more preferably 320°C.

[0040] The time of the decomposition step (step S1) (hereinafter referred to as "decomposition time") is not particularly limited, but is preferably 30 seconds to 60 minutes. A shorter decomposition time tends to yield a block copolymer with long block lengths, while a longer decomposition time tends to yield a copolymer with short block lengths (a copolymer close to a random copolymer). The upper limit of the decomposition time is more preferably 40 minutes, even more preferably 20 minutes, and even more preferably 10 minutes.

[0041] The shear rate in the decomposition process (step S1) is preferably 50 to 1,000,000 / second. More preferably, the shear rate in the decomposition process (step S1) is 100 to 500,000 / second, and even more preferably 1,000 to 300,000 / second.

[0042] The pressure inside the reaction apparatus during the decomposition process (step S1) is preferably at or above atmospheric pressure.

[0043] [Regarding conditions [A] and [B]] The method for producing a polycarbonate copolymer according to this embodiment satisfies at least one of the following conditions [A] and [B]. Condition [A]: The raw material contains the above-mentioned polyhydric alcohol (a polyhydric alcohol with 2 to 6 OH groups). Condition [B]: In the decomposition process (step S1), the ratio of (mass of water in the reaction apparatus) to (mass of raw materials) is 1.0 to 10.0%.

[0044] If at least one of conditions [A] and [B] is met, a polycarbonate copolymer can be produced without using a catalyst such as a metal oxide. Specifically, if a predetermined amount of water is present in the reaction apparatus, as in condition [B], the decomposition and bonding of the resin contained in the raw materials proceed simultaneously, and a copolymer of the first resin and the second resin can be obtained without using a catalyst. Also, if the raw materials contain a polyhydric alcohol, as in condition [A], the decomposition of the resin contained in the raw materials is promoted by the polyhydric alcohol, and a copolymer of the first resin and the second resin can be obtained.

[0045] First, we will explain the case where polyhydric alcohols are not used (i.e., the raw materials do not contain polyhydric alcohols). In this case, during the decomposition process (step S1), the ratio of (mass of water in the reactor) to (mass of raw materials) should be 1.0 to 10.0% (0.010 to 0.100) (condition [B]). Specifically, water is added to the raw materials to bring the water content in the reactor within the above range. The water may be mixed with the raw materials beforehand before they are introduced into the reactor, or it may be added to the reactor after the raw materials have been introduced.

[0046] Here, "mass of raw materials" includes the mass of the first resin, the second resin, and any other optionally added components. "Mass of raw materials" includes the mass of trace amounts of water originally adsorbed onto the raw materials, but does not include the mass of water added to the raw materials. "Mass of water in the reaction apparatus" includes both the mass of trace amounts of water originally adsorbed onto the raw materials and the mass of water added to the raw materials.

[0047] If the ratio of (mass of water in the reaction vessel) / (mass of raw materials) is within the range of 1.0 to 10.0%, the decomposition and bonding of the resin contained in the raw materials proceed simultaneously, and a copolymer of the first resin and the second resin can be obtained without the use of a catalyst. If there is too little water, a copolymer may not be obtained. On the other hand, if there is too much water, the energy cost in the drying process (step S2) increases. Also, if there is too much water, the viscosity of the resin-water mixture decreases too much, which may cause the seal formed by the resin in the reaction vessel to break and vent up. The lower limit of (mass of water in the reaction vessel) / (mass of raw materials) is preferably 2.0%, and more preferably 3.0%. The upper limit of (mass of water in the reaction vessel) / (mass of raw materials) is preferably 8.0%, and more preferably 6.0%.

[0048] Next, we will explain the case where polyhydric alcohols are used (when the raw material contains polyhydric alcohols, condition [A]). In this case, since the polyhydric alcohol promotes the decomposition of the resin contained in the raw material, the decomposition and bonding of the resin contained in the raw material proceeds with only the trace amounts of water normally adsorbed on the raw material, even without adding water to the raw material. Therefore, when using polyhydric alcohols, a copolymer of the first resin and the second resin can be obtained even if (mass of water in the reaction apparatus) / (mass of raw material) is not set to 1.0-10.0%. In other words, if condition [A] is met, a copolymer of the first resin and the second resin can be obtained even if condition [B] is not met. To put it another way, in the method for producing polycarbonate resin according to this embodiment, it is sufficient if at least one of condition [A] and condition [B] is met.

[0049] The method for producing polycarbonate resin according to this embodiment may satisfy both conditions [A] and [B]. That is, when the raw material contains a polyhydric alcohol (when condition [A] is satisfied), the ratio of (mass of water in the reaction apparatus) / (mass of raw material) may be set to 1.0 to 10.0%. Note that when the raw material contains a polyhydric alcohol, the "mass of raw material" also includes the mass of the polyhydric alcohol. Furthermore, the "mass of raw material" also includes the mass of trace amounts of water originally adsorbed on the raw material (including trace amounts of water adsorbed on the polyhydric alcohol). The "mass of water in the reaction apparatus" shall include both the mass of trace amounts of water originally adsorbed on the raw material (including trace amounts of water adsorbed on the polyhydric alcohol) and the mass of water added to the raw material.

[0050] When both conditions [A] and [B] are met, the decomposition of the resin contained in the raw material progresses more easily, which tends to result in copolymers with shorter block lengths (polymers similar to random copolymers).

[0051] However, if condition [A] is met, i.e., if the raw material contains a polyhydric alcohol, it is preferable to reduce the amount of water in the reactor. When the raw material contains a polyhydric alcohol, the reaction will proceed even if the amount of water in the reactor is low. By reducing the amount of water in the reactor, the drying process (step S2) can be shortened, and the energy costs required for drying can be reduced. In this case, copolymers with long block lengths can be obtained. Copolymers with long block lengths may be advantageous when used as compatibilizers. For example, when the raw material contains a polyhydric alcohol, it is possible to obtain the decomposition product using only the trace amounts of water that are originally adsorbed on the raw material, without intentionally adding water to the raw material.

[0052] When the raw material contains polyhydric alcohols, it is preferable that the ratio of (mass of water in the reaction vessel) / (mass of raw material) be between 0.20% and 10.0%. When the raw material contains polyhydric alcohols, the lower limit of the ratio of (mass of water in the reaction vessel) / (mass of raw material) is preferably 0.30%, and more preferably 0.50%. When the raw material contains polyhydric alcohols, the upper limit of the ratio of (mass of water in the reaction vessel) / (mass of raw material) is preferably 8.0%, and more preferably 6.0%. Furthermore, from the viewpoint of reducing energy costs required for drying, the upper limit of the ratio of (mass of water in the reaction vessel) / (mass of raw material) is preferably 1.0%, more preferably 0.90%, more preferably 0.80%, and still more preferably 0.70%.

[0053] [Drying process] In the drying step (step S2), the decomposition products obtained in the decomposition step (step S1) are dried.

[0054] The heating temperature in the drying step (step S2) is preferably 100 to 350°C. If the heating temperature is too low, it will be necessary to dry the product for a long time to reduce the moisture content. On the other hand, if the drying temperature is too high, the decomposition products will volatilize, resulting in a low yield.

[0055] The drying step (step S2) may be carried out in the reactor used in the decomposition step (step S1), or it may be carried out after transferring the product to a different container. It is preferable to carry out the drying step (step S2) in the reactor used in the decomposition step (step S1). In this case, the drying step (step S2) may be a step of discharging moisture from the reactor at a temperature of 100 to 350°C. For example, the moisture from the reactor may be discharged as vapor by operating the vent port or the like in the reactor while it is still at a high temperature after the completion of the decomposition step (step S1), and the decomposition product may be dried by holding it in that state for a predetermined time.

[0056] In the drying process (step S2), it is preferable to dry the product so that the moisture content after drying, expressed by the following formula, is 0.15% (0.0015) or less. Moisture content after drying = (Mass of water contained in decomposition products) / (Mass of raw materials)

[0057] The upper limit of the moisture content after drying is more preferably 0.13%, and even more preferably 0.12%. The lower limit of the moisture content after drying is not particularly limited, but from the viewpoint of efficiency, it is preferably 0.01%, more preferably 0.05%, and even more preferably 0.08%.

[0058] The polycarbonate copolymer is produced through the above process.

[0059] [About the reaction apparatus] The reaction apparatus used in the polycarbonate copolymer according to this embodiment is preferably an extruder capable of continuously processing the raw materials while heating and kneading them. A preferred configuration when using an extruder will be described below.

[0060] The extruder is preferably one with a total L / D ratio of 15 to 150 and twin coaxial screws with diameters of 6 to 150 mm. The lower limit of the total L / D ratio is more preferably 30. The upper limit of the total L / D ratio is more preferably 100. The lower limit of the diameter of the twin screws is preferably 10 mm, and the upper limit of the diameter of the twin screws is preferably 80 mm.

[0061] The extruder is preferably equipped with a liquid injection port for introducing moisture into the apparatus. In this case, it is preferable to provide seal zones, as described below, before and after the liquid injection port.

[0062] The seal zone is a zone having a portion where the filling rate is 100%. The seal zone includes, for example, a seal ring and screw elements positioned before and after it. The seal ring is a component that narrows the flow path of the raw material (resin) and restricts the flow of the raw material. Upstream of the seal ring (raw material inlet side), it is preferable to arrange screw elements with progressively lower feed capacity (traction flow rate) from the upstream side so that the pressure inside the cylinder gradually increases as it approaches the seal ring. The "screw elements with low feed capacity" here may be mixing elements such as a kneading disc or rotor. Furthermore, it is preferable to arrange a reverse feed screw downstream of the seal ring (die side).

[0063] In the configuration with the seal ring described above, the filling rate is 100% in the area surrounding the seal ring. The seal zone does not necessarily have to have a seal ring; it just needs to have a portion where the filling rate is 100% (hereinafter referred to as the "seal portion"). By providing seal zones before and after the liquid injection port, the area sandwiched between the two seal portions becomes airtight, allowing the moisture added from the liquid injection port to come into contact with the raw material in the form of pressurized water vapor.

[0064] It is preferable to provide a kneading zone for mixing moisture and raw materials between the two sealing sections, separate from the sealing zone. The kneading zone may include, for example, a notched flight screw, a rotor, and a kneading disc. The kneading zone may be a single continuous area, but it is preferable to divide it into two or more sections with a flight screw in between. This is because inserting a flight screw reduces the filling rate and increases the contact area between moisture and raw materials. In this case, it is preferable to provide one or more kneading zones on both the upstream and downstream sides of the liquid injection port.

[0065] In the region sandwiched between the two seals, it is preferable to lower the filling rate in order to increase the contact area between moisture and raw materials. For this reason, it is preferable to place a feeding-capable mixing element in the region sandwiched between the two seals. Here, "feeding-capable mixing element" also includes a notched flight screw. Specifically, "feeding-capable mixing element" is a notched flight screw, rotor, and kneading disc. One or more notched flight screws, rotors, and kneading discs are placed in the region sandwiched between the two seals, and it is preferable that the sum of their lengths is 100 to 5000% (L / D = 1 to 50) of the diameter D of the extruder, and more preferably 200 to 3000% (L / D = 2 to 30). The "region sandwiched between the two seals" includes both a part of the seal zone (the region inside the seals) and the kneading zone.

[0066] The extruder preferably has multiple temperature control zones. This allows for control of the overall temperature of the apparatus, or the heating temperature in the decomposition or drying process, thereby improving the efficiency of polycarbonate copolymer production.

[0067] The extruder configuration described above is merely an example, and the reaction apparatus used for the polycarbonate copolymer according to this embodiment is not limited thereto. When the raw material contains polyhydric alcohols (when condition [A] is met), the reaction proceeds even if the amount of moisture in the reaction apparatus is very small, so the reaction apparatus does not need to be equipped with a liquid injection port for introducing moisture into the apparatus.

[0068] <Polycarbonate copolymer> The polycarbonate copolymer produced by this embodiment will be described below. The composition of the polycarbonate copolymer described below is merely illustrative and does not limit the production method according to this embodiment.

[0069] [Structure etc.] The polycarbonate copolymer produced by this embodiment contains structural units derived from polycarbonate resin and structural units derived from polyester resin or polyurethane resin. Furthermore, if the raw materials contain polyhydric alcohols (polyhydric alcohols having 2 to 6 OH groups), the polycarbonate copolymer contains structural units derived from polyhydric alcohols having 2 to 6 OH groups. In addition, if the raw materials contain resins other than polycarbonate resin (first resin) and polyester resin or polyurethane resin (second resin), structural units derived from those resins may be included.

[0070] Polycarbonate copolymers are not limited to those described above, but preferably include structural units derived from aromatic polycarbonate as structural units derived from polycarbonate resin, and are particularly preferably include structural units represented by the following formula (I).

[0071] [ka]

[0072] Polycarbonate copolymers are not limited to these, but it is preferable that they contain structural units derived from polybutylene succinate or polybutylene terephthalate as structural units derived from polyester resin or polyurethane resin.

[0073] In polycarbonate copolymers, it is preferable that the proportion of structural units derived from polycarbonate resin is 10 to 90 mol% of the total polycarbonate copolymer. The lower limit of the proportion of structural units derived from polycarbonate resin is more preferably 30 mol%, and the upper limit is more preferably 70 mol%.

[0074] In polycarbonate copolymers, it is preferable that the proportion of structural units derived from polyester resin or polyurethane resin is 10 to 90 mol% of the total polycarbonate copolymer. The lower limit of the proportion of structural units derived from polyester resin or polyurethane resin is more preferably 30 mol%. The upper limit of the proportion of structural units derived from polyester resin or polyurethane resin is more preferably 70 mol%.

[0075] The ratio of structural units derived from polycarbonate resin to structural units derived from polyester resin or polyurethane resin is preferably 90:10 to 10:90 in molar ratio, and more preferably 70:30 to 30:70.

[0076] [Molecular weight, etc.] The polycarbonate copolymer preferably has a number-average molecular weight Mn of 30,000 or less. The polycarbonate copolymer preferably has a weight-average molecular weight Mw of 50,000 or less. Furthermore, the degree of dispersion (Mw / Mn) is preferably 1.0 to 5.0. The molecular weight of the polycarbonate copolymer can be adjusted by the temperature and time of the decomposition step (step S1), the amount of water added, and whether or not polyhydric alcohols are added.

[0077] By setting the molecular weight within these ranges, for example, when a polycarbonate copolymer is used as a compatibilizer, the dispersibility in the base resin is improved, and the effect as a compatibilizer is enhanced. The upper limit of the number average molecular weight Mn is more preferably 20,000, and even more preferably 15,000. The upper limit of the weight average molecular weight Mw is more preferably 40,000, and even more preferably 30,000. The lower limit of the number average molecular weight Mn is not particularly limited, but may be, for example, 8,000. The lower limit of the weight average molecular weight Mw is not particularly limited, but may be, for example, 12,000.

[0078] The polycarbonate copolymer preferably has a thermal decomposition temperature of 280°C or higher. More preferably, the thermal decomposition temperature of the polycarbonate copolymer is 300°C or higher.

[0079] [Fγ] When the polycarbonate copolymer contains the structural unit represented by the above formula (I), it is preferable that the polycarbonate copolymer has Fγ represented by the following formula less than 20% (0.20). Fγ = Iγ * / (Iγ + Iγ * ) Here, Iγ and Iγ * are values obtained from the 1 1H-NMR spectrum of the polycarbonate copolymer. Iγ is a methyl group contained in the isopropylidene group between two aromatic rings of the formula (I), and is the integrated intensity of the signal derived from the proton of the methyl group when the structural unit of the formula (I) is bonded to the structural unit of another formula (I). Iγ * is a methyl group contained in the isopropylidene group between two aromatic rings of the formula (I), and is the integrated intensity of the signal derived from the proton of the methyl group when the structural unit of the formula (I) is bonded to a structural unit other than the formula (I).

[0080] The signal derived from the methyl group of the isopropylidene group between two aromatic rings of the formula (I) appears at different chemical shifts when the structural unit of the formula (I) is bonded to the structural unit of another formula (I) and when the structural unit of the formula (I) is bonded to a structural unit other than the formula (I). Here, when the structural unit of the formula (I) is bonded to the structural unit of another formula (I), the methyl group is denoted as the γ-position methyl group, and when the structural unit of the formula (I) is bonded to a structural unit other than the formula (I), the methyl group is denoted as the γ * '-position methyl group. The signal derived from the proton of the γ-position methyl group appears at about 1.65 to 1.70 ppm, whereas the signal derived from the proton of the γ * '-position methyl group appears at a position shifted by about 0.05 to 0.10 ppm from the signal derived from the proton of the γ-position methyl group, depending also on the bonded structural unit.

[0081] Iγ and Iγ * are respectively the γ-position and γ *This is the integrated intensity of the signal originating from the proton of the methyl group at position 1. 1 The integrated signal intensity of 1H-NMR is proportional to the number of protons. Therefore, Iγ and Iγ * These are the γ position and γ * It is an amount proportional to the number of protons in the methyl group at that position.

[0082] Therefore, Iγ is a quantity proportional to the number of bonds between structural units in formula (I), and Iγ * Fγ is a quantity proportional to the number of bonds between structural units of formula (I) and structural units other than those of formula (I). Fγ = Iγ * / (Iγ+Iγ * ) is the ratio of the number of bonds between structural units of formula (I) and structural units other than those of formula (I) to the sum of the number of bonds between structural units of formula (I) and the number of bonds between structural units of formula (I) and structural units other than those of formula (I).

[0083] A larger Fγ value indicates a higher proportion of the polycarbonate copolymer bond between structural units of formula (I) and structural units other than those of formula (I). In other words, a larger Fγ value means that the switching between structural units of formula (I) and other structural units occurs more frequently, and the size of the blocks where structural units of formula (I) are continuous is smaller.

[0084] Fγ can be adjusted by the temperature and time of the decomposition process (step S1), the amount of water added, and whether or not polyhydric alcohols are added.

[0085] By keeping Fγ below 20%, the effectiveness as a compatibilizer is enhanced, for example, when a polycarbonate copolymer is used as a compatibilizer. The upper limit of Fγ is more preferably 16%, even more preferably 10%, and even more preferably 6%. The lower limit of Fγ is not particularly limited, but may be, for example, 0.1%. The lower limit of Fγ is preferably 1.0%, and even more preferably 2.0%.

[0086] [Structural units derived from polyhydric alcohols] The polycarbonate copolymer preferably contains structural units derived from a polyhydric alcohol having 2 to 6 OH groups, and more preferably contains structural units derived from a polyhydric alcohol having 3 to 6 OH groups. The structural units derived from the polyhydric alcohol are particularly preferably derived from pentaerythritol or trimethylolpropane.

[0087] In polycarbonate copolymers, it is preferable that the proportion of structural units derived from polyhydric alcohols having 2 to 6 OH groups is 0.5 to 5.0 mol% of the total polycarbonate copolymer. The lower limit of the proportion of structural units derived from polyhydric alcohols having 2 to 6 OH groups is more preferably 1.0 mol%. The upper limit of the proportion of structural units derived from polyhydric alcohols having 2 to 6 OH groups is more preferably 3.0 mol%.

[0088] It is more preferable that the polycarbonate copolymer contains structural units derived from polyhydric alcohols having three or more OH groups. By containing structural units derived from polyhydric alcohols having three or more OH groups, the polycarbonate copolymer can be given a branched structure. By giving the polycarbonate copolymer a branched structure, for example, when the polycarbonate copolymer is used as a compatibilizer, its effect as a compatibilizer is enhanced. For example, it is conceivable to set the number of branches to three and combine three or more resins to combine segments with SP values ​​of 9-10, 10-12, and 12-14.

[0089] [Application] Polycarbonate copolymers, though not limited to these, can be used as compatibilizers to improve the compatibility of two or more resins, for example.

[0090] When using a polycarbonate copolymer as a compatibilizer, it is preferable that the polycarbonate copolymer be a block copolymer from the viewpoint of improving the compatibility of two or more resins.

[0091] [Effects of this embodiment, etc.] The method for producing a polycarbonate copolymer and the polycarbonate copolymer according to one embodiment of the present invention have been described above. According to this embodiment, a polycarbonate copolymer can be produced without using a catalyst that promotes polymerization between polycarbonate and other resins, as has been done in the prior art.

[0092] Products manufactured according to this invention can achieve efficient use of resources and energy, utilization of renewable resources, and reduction of environmental impact. By providing this invention to society, we can contribute to achieving Goal 12 (Responsible Consumption and Production), one of the 17 Sustainable Development Goals (SDGs) established by the United Nations. [Examples]

[0093] The present invention will be described more specifically below with reference to examples. The present invention is not limited to these examples.

[0094] [Preparation of polycarbonate copolymers] Polycarbonate copolymers were produced using an extruder under the conditions shown in Table 1. After the decomposition process, the extruder's vent was operated at 280°C to release moisture as steam, and the mixture was held at that temperature for 15 seconds to dry.

[0095] The extruder used was a "KZW series" manufactured by Technovel Co., Ltd., with an overall L / D ratio of 45 and twin coaxial screws with a diameter of 15 mm. Figure 2 schematically shows the screw arrangement of the extruder. This extruder was equipped with a liquid injection port for introducing moisture into the apparatus, and had seal zones before and after this liquid injection port. Each seal zone consisted of a seal ring, rotor, kneading disc, and reverse feed screw, with the screw elements arranged so that the filling rate was 100% at and near the seal ring. Furthermore, a kneading zone consisting of a notched flight screw, rotor, and kneading disc was arranged in the region between the seal zones. The kneading zone was divided into an upstream side and a downstream side of the liquid injection port, with the flight screw in between. The total length of the notched flight screw, rotor, and kneading disc in the region sandwiched between the parts with a 100% filling rate (seal sections) was 1367% of the extruder's diameter D (L / D = 13.67). In samples No. 3, 4, 6, and 9, described later, water was injected through the liquid injection port to adjust the water content during decomposition.

[0096] [Table 1]

[0097] In Table 1, "PC" in the "Resin 1" column represents polycarbonate resin. Teijin Limited's "Panlite® L1225" (number average molecular weight approximately 18,000, weight average molecular weight approximately 40,000, glass transition temperature approximately 150°C) was used as the polycarbonate resin.

[0098] In Table 1, "PBS" in the "Resin 2" column represents polybutylene succinate. Mitsubishi Chemical Corporation's "FZ71" polybutylene succinate (number average molecular weight approximately 35,000, weight average molecular weight approximately 110,000, glass transition temperature approximately -40°C, melting point approximately 120°C) was used.

[0099] In Table 1, "PBT" in the "Resin 2" column represents polybutylene terephthalate. For the polybutylene terephthalate used, we used polybutylene terephthalate manufactured by Goodfellow (number average molecular weight approximately 30,000, weight average molecular weight approximately 60,000, glass transition temperature approximately 125°C, melting point approximately 230°C).

[0100] In the "Polyhydric Alcohols" column of Table 1, "A1" represents pentaerythritol and "A2" represents trimethylolpropane.

[0101] The values ​​in the "Moisture Content During Decomposition" column of Table 1 represent (mass of water in the reaction apparatus) / (mass of raw materials).

[0102] The values ​​in the "Moisture Content After Drying" column of Table 1 represent (mass of water contained in decomposition products) / (mass of raw materials).

[0103] The proportion (mol%) of constituent units of the manufactured polycarbonate copolymer is determined by proton nuclear magnetic resonance ( 1 Analysis was performed by 1H-NMR. 1 ¹H-NMR spectra were measured using a JEOL ECZR 500MHz nuclear magnetic resonance (NMR) spectrometer, by dissolving the polycarbonate copolymer in deuterated chloroform at a concentration of 10 mg / ml. Tetramethylsilane (TMS) was used as the chemical shift reference.

[0104] The number-average molecular weight (Mn) and weight-average molecular weight (Mw) were measured by gel permeation chromatography (GPC) using polystyrene as a standard substance after dissolving the prepared polycarbonate copolymer in 0.5 wt% chloroform.

[0105] The thermal decomposition temperature was determined by simultaneously measuring the weight loss while raising the temperature from 40°C to 500°C at a rate of 10°C / min in a nitrogen environment using a differential thermal and thermogravimetric analyzer (TG-DTA). The temperature at which the weight began to decrease was defined as the thermal decomposition temperature.

[0106] 1 The presence or absence of copolymer was confirmed from the 1H-NMR spectrum, and Fγ was determined.

[0107] Examples No. 1 and No. 2 are examples in which pentaerythritol (a polyhydric alcohol with 4 OH groups) was used as the polyhydric alcohol, and the raw materials (PC and PBS) were decomposed without adding water (only the trace amounts of water adsorbed on the raw materials) to produce polycarbonate copolymers.

[0108] No. 3 is an example of producing a polycarbonate copolymer without using polyhydric alcohols, by increasing the water content during decomposition. Comparing the case using polyhydric alcohols (No. 1) with the case using water (No. 3), it can be seen that using polyhydric alcohols results in a larger Fγ value and a tendency for shorter block lengths.

[0109] No. 4 is an example of producing a polycarbonate copolymer using a polyhydric alcohol and further increasing the water content during decomposition. In this case, Fγ is even larger than in No. 1, and it can be seen that the block length tends to be shorter.

[0110] Example No. 5 shows the production of a polycarbonate copolymer by changing the ratio of the raw materials PC and PBS, as in example No. 2. It can be seen that copolymers can be produced even when the ratio of PC to PBS is changed.

[0111] Case No. 6 is an example in which polycarbonate copolymer was produced using PBT instead of PBS as the second resin. In this case as well, it can be seen that copolymer was successfully produced.

[0112] Case No. 7 is an example where trimethylolpropane (a polyhydric alcohol with 3 OH groups) is used instead of pentaerythritol as the polyhydric alcohol. In this case as well, it can be seen that copolymers can be produced.

[0113] Case No. 8 is an example where copolymer could not be produced because neither polyhydric alcohol nor water was added.

[0114] No. 9 is an example of producing a copolymer by adding polyhydric alcohol and water and further extending the decomposition time. It can be seen that extending the decomposition time resulted in a copolymer with a large Fγ (a copolymer with a short block length).

[0115] [Fabrication of resin molded products] Next, using polycarbonate copolymers No. 1 and 2 as compatibilizers, resin molded articles (solid sheets) consisting of polycarbonate (PC) and low-melting-point liquid crystal polymer (LCP) were produced by extrusion. For comparison, solid sheets without compatibilizers and solid sheets using an alloy (a compound, not a copolymer) of polycarbonate and polyester as a compatibilizer were also produced.

[0116] The solid sheet thickness was 1.5 mm. Teijin Limited's Panlite® L1225L polycarbonate was used. Ueno Pharmaceutical Co., Ltd.'s low-melting-point LCP, A-8100 (melting point approximately 230°C), was used as the liquid crystal polymer. The molding temperature was 260-300°C.

[0117] The flexural modulus and yield stress of the fabricated solid sheets were measured. The results are shown in Table 2.

[0118] [Table 2]

[0119] The solid sheets of Examples 1 and 2, which used the polycarbonate copolymer according to this embodiment as a compatibilizer, showed significantly improved flexural modulus and yield stress compared to the solid sheet of Comparative Example 1, which did not use a compatibilizer. On the other hand, the solid sheet of Comparative Example 2, which used a polycarbonate-polyester alloy as a compatibilizer, did not show a significant difference in flexural modulus and yield stress compared to the solid sheet of Comparative Example 1.

[0120] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention.

Claims

1. A decomposition step in which raw materials containing polycarbonate resin and polyester resin or polyurethane resin are heated and stirred in a reaction apparatus to obtain decomposition products, The process includes a drying step for drying the decomposition products, For each of the resins contained in the raw materials, if the resin is amorphous, the reference temperature of the resin is set to the glass transition temperature of the resin + 50°C; if the resin is crystalline, the reference temperature of the resin is set to the melting point of the resin; and the heating temperature of the decomposition step is set to be equal to or higher than the highest reference temperature of the resins contained in the raw materials. A method for producing a polycarbonate copolymer that further satisfies at least one of the following conditions [A] and [B]. Condition [A]: The raw material further comprises a polyhydric alcohol having 2 to 6 OH groups. Condition [B]: In the decomposition step, (mass of water in the reaction apparatus) / (mass of the raw materials) is 1.0 to 10.0%.

2. A method for producing a polycarbonate copolymer according to claim 1, satisfying the above condition [A].

3. The method for producing a polycarbonate copolymer according to claim 2, wherein in the decomposition step, (mass of water in the reaction apparatus) / (mass of the raw materials) is 0.20 to 10.0%.

4. The method for producing a polycarbonate copolymer according to claim 2, wherein the amount of the polyhydric alcohol is 0.10 to 10.0 parts by mass per 100 parts by mass of the total amount of resin contained in the raw materials.

5. The method for producing a polycarbonate copolymer according to claim 2, wherein the number of OH groups in the polyhydric alcohol is 3 to 6.

6. The method for producing a polycarbonate copolymer according to claim 5, wherein the polyhydric alcohol is pentaerythritol or trimethylolpropane.

7. A method for producing a polycarbonate copolymer according to any one of claims 1 to 6, wherein the proportion of the polycarbonate resin is 10 to 90% by mass of the total amount of resin contained in the raw materials.

8. A method for producing a polycarbonate copolymer according to any one of claims 1 to 6, wherein the raw material includes a polyester resin.

9. The method for producing a polycarbonate copolymer according to claim 8, wherein the polyester resin is polybutylene succinate or polybutylene terephthalate.

10. The method for producing a polycarbonate copolymer according to any one of claims 1 to 6, wherein the drying step is a step of discharging moisture from the reaction apparatus at a temperature of 100 to 350°C.

11. A method for producing a polycarbonate copolymer according to any one of claims 1 to 6, wherein in the drying step, the drying is carried out so that (mass of water contained in the decomposition product) / (mass of the raw material) is 0.15% or less.

12. The reaction apparatus is an extruder having twin-screwed machines with a diameter of 6 to 150 mm. The aforementioned extruder has an overall L / D ratio of 15 to 150. The extruder has a liquid injection port for introducing moisture into the apparatus, The extruder further has sealing zones on both the upstream and downstream sides of the liquid injection port, each having a portion where the filling rate is 100%. A method for producing a polycarbonate copolymer according to any one of claims 1 to 6, wherein one or more notched flight screws, rotors, and kneading discs are arranged in a region sandwiched between the portions where the filling rate is 100%, and the sum of their lengths is 100% to 5000% of the diameter D of the extruder.

13. A polycarbonate copolymer comprising structural units derived from polycarbonate resin, structural units derived from polyester resin or polyurethane resin, and structural units derived from a polyhydric alcohol having 2 to 6 OH groups.

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