Polyoxyalkylene resin and method for preparing the same

Abstract

Provided is a polyoxyalkylene resin having excellent thermal stability and mechanical properties such as impact strength, tensile strength, and flexural strength, by using a catalyst which carries out polymerization by delaying a polymerization initiation rate. In addition, the polyoxyalkylene resin has low formaldehyde emission and a high melting point.

Description

POLYOXYALKYLENE RESIN AND METHOD FOR PREPARING THE SAME

[0001] The present invention relates to a polyoxyalkylene resin and a method for preparing the same.

[0002] Since a polyoxymethylene (POM) resin has excellent mechanical properties, creep resistance, fatigue resistance, and friction wear resistance, it is being widely used in places where complicated requirements are satisfied such as various electrical and electronic components and mechanical mechanisms.

[0003] In general, a polyoxymethylene resin produces an oxymethylene homopolymer or copolymer by bulk polymerization, solution polymerization, or suspension polymerization of trioxane alone or trioxane with cyclic ether and / or cyclic acetal. However, since the polyoxymethylene resin, in particular, the polyoxymethylene homopolymer, lacks thermal stability, it has a disadvantage of being prone to decomposition thermally, mechanically, or due to an additive during molding processing. In particular, when an unstable terminal is present in the resin, increased odor during molding, poor processability, and the like are caused.

[0004] In order to overcome the disadvantages of the polyoxymethylene homopolymer, a method of randomly dispersing and introducing a copolymer obtained by copolymerizing a specific comonomer, that is, cyclic ether such as ethylene oxide or cyclic formal such as dioxolane in the presence of a catalyst with formaldehyde, trioxane, and the like in / into a homopolymer was also suggested.

[0005] In addition, when a polymerization initiation time of a catalyst during polymerization of the polyoxymethylene resin is too fast, the molecular distribution of the polymer is increased, and thus, problems such as deterioration of thermal properties or mechanical properties arise. In order to solve the problem, development of a catalyst which delays polymerization initiation rate(propagation time) is needed. In addition, when a catalyst which delays the polymerization initiation time is used, depolymerization following polymerization delay may occur, and thus, development of a catalyst to solve both problems is needed.

[0006] However, the problems were not able to be sufficiently solved with conventional polymerization catalysts, and thus, research and development of a new polymerization catalyst for polymerization of a polyoxymethylene resin are urgently needed.

[0007] An object of the present invention is to provide a method for preparing a new polyoxyalkylene resin which delays a polymerization initiation time more than conventional methods, reduces formaldehyde emission, and has excellent thermal stability and mechanical properties, and a polyoxyalkylene resin prepared therefrom.

[0008] In order to achieve the object described above, the present inventors continuously conducted studies, and as a result, they found that when a new polymerization catalyst is used at a certain content to prepare a polyoxyalkylene resin, a resin which is polymerized with a slower polymerization initiation rate than conventional methods and also has excellent mechanical properties and thermal properties may be prepared, thereby completing the present invention.

[0009] In one general aspect, a polyoxyalkylene resin prepared from a polymerizable composition comprising a cyclic acetal monomer and a cyclic boron trifluoride compound is provided.

[0010] According to an exemplary embodiment of the present invention, the cyclic boron trifluoride may have 3 to 30 carbon atoms.

[0011] According to an exemplary embodiment of the present invention, the cyclic boron trifluoride compound may be represented by the following Chemical Formula 1:

[0012] [Chemical Formula 1]

[0013]

[0014] According to an exemplary embodiment of the present invention, the cyclic boron trifluoride may be included at 0.01 to 3 parts by weight with respect to 100 parts by weight of the cyclic acetal monomer.

[0015] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may have 2 to 15 carbon atoms.

[0016] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may further include dioxane, trioxane, and tetraoxane-based monomer, and for example, may mainly include any one or two or more selected from the group consisting of 1,3-dioxolane, 1,4-dioxepane, 1,3,5-trioxane, and the like.

[0017] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may be included in an amount of 90 wt% or more with respect to the total polymerizable composition.

[0018] According to an exemplary embodiment of the present invention, the polymerizable composition may further include a linear acetal monomer.

[0019] According to an exemplary embodiment of the present invention, the linear acetal monomer may be included at 0.01 to 5 parts by weight with respect to 100 parts by weight of the cyclic acetal monomer.

[0020] According to an exemplary embodiment of the present invention, the polymerizable composition may further include a comonomer such as a cyclic ether-based monomer or a cyclic formal-based monomer in addition to the monomer. The cyclic formal includes 1,3-dioxolane, diethylene glycol formal, 1,3-propanediol formal, 1,4-butanediol formal, 1,3-dioxetane, 1,3,5-trioxetane, 1,3,6-trioxocane, and the like.

[0021] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may include a repeating unit represented by the following Chemical Formula 2:

[0022] [Chemical Formula 2]

[0023]

[0024] wherein

[0025] R1and R2are independently of each other hydrogen, methyl, or ethyl, and n is an integer of 1 or more.

[0026] According to an exemplary embodiment of the present invention, a speed represented by polymerization initiation time (initial propagation time) of the polyoxyalkylene resin during polymerization may be 4 seconds or more.

[0027] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a melting point (Tm) of 170℃ or more.

[0028] Since the polyoxyalkylene resin of the present invention has a slower polymerization initiation rate than conventional methods, polymerization is initiated after the monomer is well dispersed during the polymerization process, and thus, the mechanical properties and thermal physical properties of the produced resin are excellent. That is, the resin may have excellent thermal stability and mechanical properties such as impact strength, tensile strength, and flexural strength.

[0029] In addition, it generates low formaldehyde emissions and a high melting point to have excellent thermal properties.

[0030] Hereinafter, the present invention will be described in more detail with reference to specific examples and exemplary embodiments comprising the accompanying drawings. However, the following specific examples or exemplary embodiments are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

[0031] In addition, unless otherwise defined, all technical terms and scientific terms have the same meanings as those commonly understood by one of those skilled in the art to which the present invention pertains. The terms used herein are only for effectively describing a certain specific example and are not intended to limit the present invention.

[0032] In addition, the singular form used in the specification and claims appended thereto may be intended to also include a plural form, unless otherwise indicated in the context.

[0033] In addition, units used in the present specification without particular mention are based on weights, and as an example, a unit of % or ratio refers to a wt% or a weight ratio and wt% refers to wt% of any one component in a total composition, unless otherwise defined.

[0034] In addition, unless explicitly described to the contrary in the present specification, a part "comprising" a constituent element will be understood to imply further inclusion of other constituent elements rather than the exclusion of any other constituent elements.

[0035] In addition, the numerical range used in the present specification may include all values within the range comprising the lower limit and the upper limit, increments logically derived in a form and span in a defined range, all double limited values, and all possible combinations of the upper limit and the lower limit in the numerical range defined in different forms. Unless otherwise particularly defined in the present specification, values which may be outside a numerical range due to experimental error or rounding off of a value are also included in the defined numerical range.

[0036] The term "resin" in the present specification refers to a high molecular material and includes a polymer and a copolymer.

[0037] The term "alkyl" in the present specification includes both straight chain and branched chain forms, and may have 1 to 30 carbon atoms, specifically 1 to 20 carbon atoms.

[0038] Hereinafter, the polyoxyalkylene resin and the method for preparing the same according to an exemplary embodiment of the present invention will be described in more detail.

[0039] The present invention provides a polyoxyalkylene resin prepared from a polymerizable composition comprising a cyclic acetal monomer and a cyclic boron trifluoride compound is provided.

[0040] According to an exemplary embodiment of the present invention, the cyclic boron trifluoride is a cyclic BF3coordination compound polymerization catalyst and may have 3 to 30, 3 to 15, 3 to 10, 3 to 7, or 3 to 5 carbon atoms.

[0041] According to an exemplary embodiment of the present invention, the cyclic boron trifluoride compound may be represented by the following Chemical Formula 1:

[0042] [Chemical Formula 1]

[0043]

[0044] According to an exemplary embodiment of the present invention, the cyclic boron trifluoride compound may be included at 0.01 to 3 parts by weight, 0.01 to 1 part by weight, 0.05 to 0.5 parts by weight, or 0.1 to 0.3 parts by weight with respect to 100 parts by weight of the cyclic acetal monomer.

[0045] According to an exemplary embodiment of the present invention, an adduct form with a salt (for example, carboxylic acid salt) as in the conventional art or the cyclic boron trifluoride compound alone, not the composite catalyst of two may be used as a catalyst. When the adduct is used as a catalyst as before, an electronic atmosphere may be affected in the boron center of the boron trifluoride compound to change a Lewis acid or change steric hindrance around a reaction center, which may adversely affect the speed and selectivity of a polymerization reaction. However, when the cyclic boron trifluoride compound according to an exemplary embodiment is used alone as a catalyst, a polymerization time may be significantly shortened, and a polyoxyalkylene resin which produces low formaldehyde emission even with a short reaction time and has excellent thermal stability and mechanical properties may be prepared.

[0046] When the catalyst is used, the polymerization initiation time to be desired in the present invention may be delayed, and also, the thermal and mechanical properties of the polymerized material prepared therefrom are excellent and formaldehyde emission may be significantly lowered, which is thus preferred.

[0047] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may have 1 to 30, 1 to 15, 2 to 15, 2 to 10, or 2 to 5 carbon atoms.

[0048] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may include any one or two or more selected from the group consisting of 1,3-dioxolane, 1,3,5-trioxane, and the like. Preferably, it may be trioxane or a mixture of trioxane and dioxolane.

[0049] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may include trioxane and other types of cyclic acetal comonomer. Examples of the cyclic acetal comonomer may include cyclic formal-based monomers such as 1,3-dioxolane, diethylene glycol formal, 1,3-propanediol formal, 1,4-butanediol formal, 1,3-dioxetane, 1,3,5-trioxetane, 1,3,6-trioxocane, and the like. The cyclic acetal comonomer may be a 4- to 15-membered, 5- to 12-membered, or 5- to 10-membered cyclic acetal comonomer. When a cyclic ether compound is included instead of the cyclic acetal compound as a comonomer, reactivity may be lowered so that the physical properties to be desired in the present application may not be achieved, which is thus not preferred, and the polymerizable composition may not include the cyclic ether compound.

[0050] According to an exemplary embodiment of the present invention, the monomer included in the polymerizable composition may be formed of the acetal monomer, thereby having better reactivity.

[0051] Herein, the cyclic acetal comonomer may be included at 0.1 to 100 parts by weight, 1 to 50 parts by weight, or 3 to 15 parts by weight, but is not limited thereto.

[0052] According to an exemplary embodiment of the present invention, the cyclic acetal monomer may be included in an amount of 90 wt% or more, 90 to 99.9 wt%, or 95 to 99.5 wt% with respect to the total polymerizable composition.

[0053] According to an exemplary embodiment of the present invention, the polymerizable composition may further include alkyl substituted phenol or acetals as a chain transferring agent, and preferably, may include a linear acetal compound. The linear acetal compound may have 1 to 30, 1 to 15, 2 to 15, 2 to 10, or 2 to 7 carbon atoms. A non-limiting example of the linear acetal monomer may include dimethoxymethane, dimethoxyethane, diethoxyethane, diethoxymethane, and the like. The linear acetal monomer may be included at 0.01 to 50 parts by weight, 0.01 to 20 parts by weight, 0.01 to 5 parts by weight, or 0.1 to 3 parts by weight with respect to 100 parts by weight of the cyclic acetal monomer.

[0054] According to an exemplary embodiment of the present invention, the polymerizable composition may further include a common or known polymerization inhibitor. When a polyoxyalkylene having a molecular weight of 10,000 to 500,000 g / mol is obtained by the polymerization reaction of the monomer, the polymerization inhibitor is added to stop the polymerization reaction. The polymerization inhibitor is not limited as long as it may effectively stop the polymerization reaction, and may be, for example, triphenylphosphate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, alkylated formamideacetal, or a melamine-based polymerization inhibitor such as hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, or hexabutoxymethylmelamine. The polymerization inhibitor may be added in an amount of 0.01 to 50 molar times(equivalents), preferably 0.05 to 10 molar times(equivalents) the polymerization catalyst.

[0055] In addition, the polymerization inhibitor may be added as it is, or added in a state of being dissolved in an organic solvent. Herein, the organic solvent to be used may include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexane, n-heptane, and cyclohexane, alcohols such as methanol, halogenated hydrocarbons such as chloroform, dichloromethane, and 1,2-dichloromethane, and ketone such as acetone and methyl ethyl ketone.

[0056] According to an example of the present invention, an additive commonly used in the art may be further added, if necessary. Specifically, for example, an antioxidant, formaldehyde, or a formic acid remover, a terminal stabilizer, a filler, a coloring agent, a lubricant, a releasing agent, an antistatic agent, a flame retardant, a reinforcing agent, a light stabilizer, a pigment, and the like may be included. The content of the additive may be used in a range which does not substantially adversely affect the physical properties of the composition of the present invention. Specifically, an example of the antioxidant may be sterically hindered bisphenol, and for example, a product manufactured and sold under the name of Irganox 1010 from Ciba-Geigy, which is tetra-bis[methylene(3,5-di-t-butyl-4-hydrocinnamate)]methane, and the like may be used.

[0057] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin is prepared by polymerizing the cyclic acetal monomer described above in the presence of the cyclic boron trifluoride compound polymerization catalyst described above, and may be prepared as a copolymer comprising various types of repeating units depending on the additionally included monomer. In addition, the polyoxyalkylene resin may be a random copolymer or a block copolymer.

[0058] The polymerization may be carried out in the form of bulk polymerization, suspension polymerization, or solution polymerization, and a temperature of the polymerization reaction may be in a range of 0 to 100℃, preferably 20 to 80℃. As other conditions, common or known conditions may be adopted without limitation.

[0059] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may be a homopolymer comprising only a single repeating unit or a copolymer comprising two or more repeating unit. Specifically, the polyoxyalkylene resin may include a repeating unit represented by the following Chemical Formula 2:

[0060] [Chemical Formula 2]

[0061]

[0062] wherein R1and R2are independently of each other hydrogen, methyl, or ethyl, and n is an integer of 1 or more.

[0063] According to an exemplary embodiment of the present invention, in Chemical Formula 2, R1and R2may be independently of each other hydrogen or methyl, and n may be 1 or 2.

[0064] According to another exemplary embodiment of the present invention, in Chemical Formula 2, R1and R2may be independently of each other hydrogen, methyl, or ethyl (both are not hydrogen), and n may be 2 to 6.

[0065] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a weight average molecular weight of 10,000 to 500,000 g / mol, 20,000 to 200,000 g / mol, or 50,000 to 100,000 g / mol.

[0066] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a melting point (Tm) of 160℃ or higher, 170℃ or higher, 170 to 200℃, or 173 to 190℃.

[0067] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a melt index (190℃, 2.16 kg / 10 min) of 10 g / 10 min or less, 9 g / 10 min or less, 0.01 to 8 g / 10 min, 0.01 to 7.5 g / 10 min, or 0.1 to 7.0 g / 10 min.

[0068] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a tensile strength of 1 to 100 MPa, 10 to 90 MPa, 50 to 85 MPa, or 65 to 80 MPa.

[0069] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a yield elongation of 1 to 50%, 5 to 20%, or 7 to 15%.

[0070] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a flexural strength of 1 to 200 MPa, 10 to 150 MPa, 50 to 100 MPa, or 85 to 95 MPa.

[0071] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have a flexural modulus of 1,000 to 10,000 MPa, 1,500 to 8,000 MPa, or 2,000 to 5,000 MPa.

[0072] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have an impact strength of 1 to 50 kJ / m2, 5 to 20 kJ / m2, or 7 to 15 kJ / m2.

[0073] According to an exemplary embodiment of the present invention, the polyoxyalkylene resin may have formaldehyde emission of 10 mg / kg or less, 9 mg / kg or less, 8 mg / kg or less, or 7 mg / kg or less and more than 0 mg / kg.

[0074] According to an exemplary embodiment of the present invention, a polymerization initiation rate (initial propagation time, sec) of the polyoxyalkylene resin during polymerization may be 3 seconds or more, 4 seconds or more, 5 seconds or more, 6 seconds or more, or 6.5 seconds or more and less than 20 seconds.

[0075] Hereinafter, the present invention will be described in more detail with reference to the examples and the comparative examples. However, the following examples and comparative examples are only an example for describing the present invention in more detail, and do not limit the present invention in any way.

[0076] [Method of evaluating physical properties]

[0077] 1) Formaldehyde emission (ECH2O)

[0078] According to the VDA275 standard specification, the obtained polyoxyalkylene resin composition was molded into a size of 100 mmХ40 mmХ2 mm and fixed in a 1 L bottle containing 50 ml of water so that it did not touch water, and the bottle was sealed. The bottles prepared as such were allowed to stand at 60℃ for 3 hours, and then as a formaldehyde content captured in water, a color development degree was analyzed using a UV spectrophotometer to measure the formaldehyde emission of a molded article. A smaller value showed better thermal stability.

[0079] 2) Melt index (MI) [g / 10 min]

[0080] The weight of a resin sample prepared by extrusion for 10 minutes at 190℃ under a load of 2.16 kg in an orifice having a constant inside diameter was measured, the value was a measure for evaluating a depolymerization rate of the resin, and a larger melt index value showed a higher depolymerization rate.

[0081] 3) Weight average molecular weight (Mw) [g / mol]

[0082] The weight average molecular weight was measured using gel permeation chromatography (GPC) equipment available from Futecs. The equipment included a mobile phase pump (Gradient Pump), a column heater (AT-4000), a detector (Shodex 201H R.I Detector), and an injector (NS-6000, automatic injector), HFIP 800 Series available from Shodex was used as an analysis column, and 7 polymethylmethacryl (PMMA) STDs were used as a standard material. HPLC-grade hexafluoroisopropanol (HFIP) was used as a mobile phase solvent, and the measurement was performed under the conditions of a column heater temperature of 40℃ and a mobile phase solvent flow rate of 0.7 mL / min. Polyoxyalkylene prepared for sample analysis was dissolved in hexafluoroisopropanol (HFIP) as the mobile phase solvent, and then the solution was injected into GPC equipment to measure the weight average molecular weight.

[0083] 4) Tensile strength [MPa] and yield elongation [%]

[0084] The tensile strength was measured using a Universal testing machine (UTM) in accordance with ISO 527-1 and ISO 527-2 standard specifications, and a tensile specimen was evaluated 5 times for each sample at a crosshead speed of 50 mm / min and the average was calculated.

[0085] 5) Flexural strength and flexural modulus [MPa]

[0086] The flexural strength and the flexural modulus were measured using a Universal testing machine (UTM) in accordance with ISO 178 standard specification, and the evaluation was performed 5 times for each sample and the average value was calculated.

[0087] 6) Impact strength [kJ / m2]

[0088] Charpy impact strength was measured using the ISO 179-1 and ISO 179-2 standard specifications, and the measurement was performed using a specimen notched at room temperature (25℃) with a Charpy impact tester No. 258D manufactured by Yasuda Seiki Seisakusho, Ltd. under an environment of 25℃. The impact strength was evaluated 5 times for each sample and the average value was calculated.

[0089] 7) Melting point (Tm) [℃]

[0090] Measurement was performed under an environment from 0℃ to 230℃ under the conditions of a heating rate of 10℃ / min, using a differential scanning calorimeter (DSC) analysis instrument.

[0091] 8) Polymerization initiation rate (initial propagation time, Tp, s (sec))

[0092] A time taken from introduction of a polymerization catalyst to a monomer to production of initial white turbidity was measured. After a certain period of time has passed since the polymerization catalyst was added to the monomer, white turbidity occurred rapidly, and the point at which the white turbidity occurred rapidly was observed using a high-speed camera capable of shooting at 50 frames or more per second and the time taken from the introduction of the polymerization catalyst to occurrence of the white turbidity was recorded as a growth rate(propagation time) during polymerization.

[0093] [Example 1]

[0094] A 1 L polymerizer was maintained at 50℃, 500 g of trioxane and 0.5 g of dimethoxymethane (Methylal) were injected using a quantitative injection device, and 0.5 g of boron trifluoride-tetrahydrofuran (BF3-THF) as a polymerization catalyst was added. 15 minutes after adding the polymerization catalyst, hexamethoxymethylmelamine (CYTEC, CYMEL303) as a polymerization inhibitor was dissolved in benzene in an amount of 0.170 g which was 1.0 molar times the polymerization catalyst and added, and the reaction was completed after 15 minutes to obtain a polyoxymethylene resin.

[0095] The physical properties of the polyoxymethylene resin were evaluated by the measurement method described above and the results are shown in the following Table 1.

[0096] [Example 2]

[0097] The process was carried out in the same manner as in Example 1, except that 1.0 g of BF3-THF as the polymerization catalyst was added.

[0098] [Example 3]

[0099] The process was carried out in the same manner as in Example 1, except that 1.5 g of BF3-THF as the polymerization catalyst was added.

[0100] [Example 4]

[0101] The process was carried out in the same manner as in Example 1, except that 1.0 g of dimethoxymethane was added.

[0102] [Example 5]

[0103] The process was carried out in the same manner as in Example 4, except that 1.0 g of BF3-THF as the polymerization catalyst was added.

[0104] [Example 6]

[0105] The process was carried out in the same manner as in Example 4, except that 1.5 g of BF3-THF as the polymerization catalyst was added.

[0106] [Example 7]

[0107] The process was carried out in the same manner as in Example 1, except that 1.5 g of dimethoxymethane was added.

[0108] [Example 8]

[0109] The process was carried out in the same manner as in Example 7, except that 1.0 g of BF3-THF as the polymerization catalyst was added.

[0110] [Example 9]

[0111] The process was carried out in the same manner as in Example 7, except that 1.5 g of BF3-THF as the polymerization catalyst was added.

[0112] [Example 10]

[0113] The process was carried out in the same manner as in Example 6, except that when adding trioxane, 10 g of dioxolane was further added.

[0114] [Example 11]

[0115] The process was carried out in the same manner as in Example 6, except that when adding trioxane, 20 g of dioxolane was further added.

[0116] [Example 12]

[0117] The process was carried out in the same manner as in Example 6, except that when adding trioxane, 30 g of dioxolane was further added.

[0118] [Comparative Example 1]

[0119] The process was carried out in the same manner as in Example 4, except that boron trifluoride diethyl etherate (BF3OEt2) was added in the equal amount instead of BF3-THF as the polymerization catalyst.

[0120] [Comparative Example 2]

[0121] The process was carried out in the same manner as in Example 5, except that boron trifluoride diethyl etherate (BF3OEt2) was added in the equal amount instead of BF3-THF as the polymerization catalyst.

[0122] [Comparative Example 3]

[0123] The process was carried out in the same manner as in Example 6, except that boron trifluoride diethyl etherate (BF3OEt2) was added in the equal amount instead of BF3-THF as the polymerization catalyst.

[0124] [Comparative Example 4]

[0125] The process was carried out in the same manner as in Example 11, except that boron trifluoride diethyl etherate (BF3OEt2) was added in the equal amount instead of BF3-THF as the polymerization catalyst.

[0126] [Comparative Example 5]

[0127] The process was carried out in the same manner as in Example 11, except that boron trifluoride dimethyl etherate (BF3OMe2) was added in the equal amount instead of BF3-THF as the polymerization catalyst.

[0128] MITensile strengthYield elongationFlexural strengthFlexural modulusImpact strengthTmECH2OTpUnitg / 10 minMPa%MPaMPakJ / m2℃mg / kgsExample 11.66412842,600101697.96.8Example 23.26611882,65081708.26.9Example 35.66911912,70071728.76.6Example 42.26912902,700131707.86.1Example 54.27111962,750121728.15.9Example 66.87411972,850111758.86.2Example 73.66813902,700131727.95.6Example 86.07112922,750121748.25.3Example 98.47511952,800111768.65.4Example 106.66910912,700121716.06.4Example 117.07010922,800141684.86.5Example 126.9649872,650131664.26.8Comparative Example 14.66012792,4001016810.53.6Comparative Example 27.06111822,500917011.13.2Comparative Example 39.26310842,600817211.82.8Comparative Example 48.86010832,55091686.82.9Comparative Example 58.2601081250091659.92.2

[0129] As seen in Table 1, it was found that when the cyclic boron trifluoride compound was used as the polymerization catalyst, the polymerization initiation propagation time was significantly increased as compared with the comparative examples. For example, when the catalyst of the present invention was used, the polymerization initiation propagation time was increased by 2 times or more in all examples, and this means that the polymerization was not carried out as soon as the catalyst was added, then was carried out after sufficient dispersion with monomers. By extending the polymerization initiation propagation time, as reviewed in the present invention, when Example 4 and the comparative example which was the same as Example 4 except that the catalyst did not belong to the present invention were compared, it was found that the tensile strength was decreased from 69 to 60, the flexural strength was decreased from 90 to 79, and the flexural modulus was decreased from 2700 to 2400, and thus, the mechanical properties were excellently increased by using the catalyst of the present invention.In addition, the formaldehyde emission of Example 4 was increased from 7.8 mg / kg to 10.5 mg / kg as compared with Comparative Example 1, and thus, it was found that the catalyst of the present invention significantly decreased the formaldehyde emission. In addition, it was confirmed from Table 1 that thermal properties were excellently increased.

[0130] In addition, when the same embodiments, Example 5 and Comparative Example 2, Example 6 and Comparative Example 3, and Example 11 and Comparative Example 4 were compared, the polyoxymethylene resin according to an exemplary embodiment showed significantly increased mechanical properties and thermal properties and low formaldehyde emission, as seen in Table 1.

[0131] Therefore, it was confirmed that a polyoxymethylene resin having effects of a high melting point, excellent mechanical properties and thermal stability, and low formaldehyde emission may be prepared by the effect of delaying the polymerization initiation rate(propagation time) according to the present invention.

[0132] Hereinabove, although the present invention has been described by specific matters and limited exemplary embodiments, they have been provided only for assisting in the entire understanding of the present invention, and the present invention is not limited to the exemplary embodiments. Various modifications and changes may be made by those skilled in the art to which the present invention pertains from this description.

[0133] Therefore, the spirit of the present invention should not be limited to the above-described exemplary embodiments, and the following claims as well as all modified equally or equivalently to the claims are intended to fall within the scope and spirit of the invention.

Claims

1.A polyoxyalkylene resin prepared from a polymerizable composition comprising a cyclic acetal monomer and a cyclic boron trifluoride compound.2.The polyoxyalkylene resin of claim 1, wherein the cyclic boron trifluoride compound has 3 to 10 carbon atoms.3.The polyoxyalkylene resin of claim 1, wherein the cyclic boron trifluoride compound is represented by the following Chemical Formula 1:[Chemical Formula 1]4.The polyoxyalkylene resin of claim 1, wherein the cyclic boron trifluoride compound is comprised at 0.01 to 1 part by weight with respect to 100 parts by weight of the cyclic acetal monomer.5.The polyoxyalkylene resin of claim 1, wherein the cyclic acetal monomer has 2 to 15 carbon atoms.6.The polyoxyalkylene resin of claim 1, wherein the cyclic acetal monomer comprises any one or two or more selected from the group consisting of 1,3-dioxolane, 1,4-dioxepane, and 1,3,5-trioxane.7.The polyoxyalkylene resin of claim 1, wherein the cyclic acetal monomer is comprised at 90 wt% or more with respect to the total polymerizable composition.8.The polyoxyalkylene resin of claim 1, wherein the polymerizable composition further comprises a linear acetal monomer.9.The polyoxyalkylene resin of claim 8, wherein the linear acetal monomer is comprised at 0.01 to 5 parts by weight with respect to 100 parts by weight of the cyclic acetal monomer.10.The polyoxyalkylene resin of claim 1, wherein the polymerizable composition further comprises a cyclic formal-based comonomer.11.The polyoxyalkylene resin of claim 1, wherein the polyoxyalkylene resin comprises a repeating unit represented by the following Chemical Formula 2:[Chemical Formula 2]whereinR1and R2are independently of each other hydrogen, methyl, or ethyl, andn is an integer of 1 or more.12.The polyoxyalkylene resin of claim 1, wherein a polymerization initiation rate (initial propagation time, sec) during polymerization is 4 seconds or more.13.The polyoxyalkylene resin of claim 1, wherein the polyoxyalkylene resin has a melting point (Tm) of 170℃ or higher.

Images