CN111454448B

CN111454448B - Polyamide and method for producing same

Info

Publication number: CN111454448B
Application number: CN202010278405.7A
Authority: CN
Inventors: 任汉邦; 陈文崇
Original assignee: Sumika Technology Co Ltd
Current assignee: Sumika Technology Co Ltd
Priority date: 2019-05-14
Filing date: 2020-04-10
Publication date: 2023-03-28
Anticipated expiration: 2040-04-10
Also published as: TW202041568A; TWI733110B; CN111454448A

Abstract

The present disclosure relates to a polyamide and a method for producing the same. The polyamide comprises a first repeat unit of formula (I), a second repeat unit of formula (II), a third repeat unit of formula (III), and a fourth repeat unit of formula (IV):

wherein, the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit are arranged randomly, in a block way or alternatively, and the carbonyl terminal (-CO-) in the formula (I) and the formula (III) is connected with the amino terminal (-NH-) in the formula (II) or the formula (IV). R ¹ 、R ² Ar, and R ³ The definition of (A) is as described later. The polyamides of the invention combine high transparency with sufficient mechanical strength.

Description

Polyamide and method for producing same

Technical Field

The present application relates to polymers, and in particular to polyamides, and methods of making the polyamides.

Background

Since polyamide has good mechanical properties, heat resistance, abrasion resistance, chemical resistance and self-lubricity, and is easy to process, polyamide is a widely used engineering plastic nowadays, widely used in electric and electronic materials such as automobiles, aerospace field, flexible circuit boards, adhesives and coating agents, and the demand thereof is still high. However, in order to use polyamide as an optical material, it is necessary to have more stringent requirements for the optical properties of such a material, for example, extremely high transmittance for visible light.

Thus, while existing polyamide materials have generally met with a variety of needs, they have not been satisfactory in all respects, and there remains a need for improvements in polyamide materials.

Disclosure of Invention

The object of the present invention is to provide a polyamide having both high transparency and sufficient mechanical strength.

It is another object of the present invention to provide a process for producing a polyamide having both high transparency and sufficient mechanical strength.

Some embodiments of the present disclosure provide a polyamide comprising a first repeat unit of formula (I), a second repeat unit of formula (II), a third repeat unit of formula (III), and a fourth repeat unit of formula (IV):

wherein, the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit are arranged randomly, in a block way or alternatively, and the carbonyl terminal (-CO-) in the formula (I) and the formula (III) is connected with the amino terminal (-NH-) in the formula (II) or the formula (IV). R is ¹ 、R ² Ar, and R ³ The definition of (b) is as described later.

Some embodiments of the present disclosure provide a method for producing a polyamide, comprising (a) providing a polyamide as described above, and (b) adding C to the polyamide as described above ₉ -C ₂₁ Aromatic tribasic acid, C ₁₀ -C ₂₂ Aromatic tetrabasic acid, C ₅ -C ₁₈ Saturated aliphatic tribasic acids, or C ₆ -C ₁₉ Saturated aliphatic tetrabasic acid to react.

Compared with the prior art, the polyamide of the invention has the advantages that: the polyamide material with high transparency and sufficient mechanical strength is obtained by using specific bisamino units and dicarbonyl units in polyamide to adjust the crystal structure and/or the size of crystal grains (crystal regions) in the polyamide.

In order to make the features and advantages of the embodiments of the present disclosure comprehensible, preferred embodiments accompanied with figures are described in detail below.

Detailed Description

The polyamide provided herein and the method for producing the polyamide are described in detail below. It is to be understood that the following description provides many different embodiments, or examples, for implementing different aspects of embodiments of the disclosure. The specific components and arrangements described below are merely illustrative of some embodiments of the disclosure for simplicity and clarity. These are, of course, merely examples and are not intended to be limiting.

Further, it should be understood that although the terms "first", "second", etc. are used herein to describe various elements, components, or sections, these elements, components, or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.

As used herein, the terms "about", "approximately", "substantially" generally mean within 5%, preferably within 3%, more preferably within 1%, or within 2%, or within 1%, or within 0.5% of a given value or range. The amounts given herein are approximate amounts, i.e., the meaning of "about", "about" and "substantially" may be implied without specifically stating "about", "about" and "substantially".

In the present specification, a range represented by "one numerical value to another numerical value" is a general expression avoiding all numerical values in the range being enumerated in the specification. Thus, unless otherwise indicated herein or otherwise clearly contradicted by reasonable or ordinary skill in the art, a particular range of values is disclosed, i.e., any value in the range is equivalent to any value in the range and any smaller range of values defined by any value in the range (including integers and values taken to the next digit of the decimal point) is intended to be encompassed by the present disclosure as if any value in the range and the smaller range were specifically and individually indicated to be encompassed by the present disclosure. For example, when only 1 to 10 is recited, it is equivalent to the disclosure of the ranges "3 to 5" and "2.5 to 6.8", regardless of whether other numerical values are recited in the specification.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized manner unless expressly so defined in the context of an embodiment of the present disclosure.

Because the molecular chain of the traditional polyamide compound has amide groups with larger polarity, and compared with other groups, the molecular acting force among the amide groups is stronger, so that the polymer chains are easy to regularly arrange to form larger crystal grains or crystal regions (such as crystal grains or crystal regions with the wavelength scale of visible light). Thus, visible light is scattered by the crystals or crystalline regions of this dimension, so that on a macroscopic scale, the appearance of conventional polyamides is cloudy or colored, and such materials cannot be used in components requiring high transparency, such as optical components.

The polyamide material with high transparency and sufficient mechanical strength is obtained by using specific diamino units and dicarbonyl units in polyamide to adjust the crystal structure and/or the size of crystal grains (crystal regions) in the polyamide.

According to some embodiments, there is provided a polyamide comprising a first repeat unit of formula (I), a second repeat unit of formula (II), a third repeat unit of formula (III), and a fourth repeat unit of formula (IV).

Wherein the carbonyl terminal (-CO-) in the formula (I) and the formula (III) may be linked to the amino terminal (-NH-) in the formula (II) or the formula (IV), and the arrangement of the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit is not particularly limited, i.e., may be an alternating arrangement, a block arrangement, a random arrangement, or the like. Each of the repeating units will be described in detail below.

[ first repeating Unit ]

In some embodiments, R in formula (I) ¹ Is straight-chain, branched or cyclic C ₂ -C ₁₅ Alkylene groups (e.g. methylene, ethylene, propylene, methylethylene, butylene, 1-methyl)Propylidene, 2-methylpropylidene, 2-ethylpropylidene, pentylidene, methylbutylidene, 1, 2-dimethylpropylidene, 1-ethylpropylidene, hexylidene, methylpentylidene, n-heptylidene, n-octylidene, n-nonylidene, n-decylidene, n-undecylidene, n-dodecylidene, n-tridecylidene, n-tetradecylidene, n-pentadecylidene,

cyclopentylene, cyclohexylene, methylcyclohexylene, methylene-cyclohexylene, etc.), preferably may be linear, branched or have a cyclic C ₄ -C ₁₂ An alkylene group. In some embodiments, to provide sufficient mechanical strength to the polyamide, it still requires some degree of crystallinity when R in formula (I) is present ¹ C which may be linear ₂ -C ₁₅ Or C ₄ -C ₁₂ Alkylene group, or C having at most two branches ₂ -C ₁₅ Or C ₄ -C ₁₂ An alkylene group, and the carbon numbers of the two branches are independently an integer of 3 or less. R ¹ The term "branched chain" as used herein refers to a branched carbon chain having a side chain on the main chain formed by the two carbon atoms connected from the beginning to the end. Therefore, the temperature of the molten metal is controlled, for example, device for selecting or keeping>

I.e. an alkylene group having four branches in the main chain.

In some embodiments, the backbone length of the first repeat unit, e.g., R, can be further controlled to impart suitable flexibility and glass transition temperature (Tg) to the polyamide being formed to increase processability and heat resistance ¹ C which may be linear ₂ -C ₈ Alkylene group, or C having at most two branches ₂ -C ₈ Alkylene groups, and the carbon numbers of the two branched chains are integers less than or equal to 3 respectively.

[ second repeating Unit ]

R in the formula (II) ² C being a straight chain ₂ -C ₁₅ Alkylene group, or C having at most two branches ₂ -C ₁₅ Alkylene groups, and the carbon numbers of the two branched chains can be respectively integers less than or equal to 3, so that the formed polyamide still has certain crystallinity to provide enough mechanical strength for the formed polyamide. In some embodiments, R ² Can be a methylene group, an ethylene group, a propylene group, a methylethylene group, a butylene group, a 1-methylpropylene group, a 2-ethylpropylene group, a pentylene group, a methylbutylene group, a1, 2-dimethylpropylene group, a 1-ethylpropylene group, a hexylene group, a methylpentylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, an n-decylene group, an n-undecylene group, an n-dodecylene group, an n-tridecylene group, an n-tetradecylene group, an n-pentadecylene group.

In some embodiments, the backbone length of the second repeat unit, e.g., R, can be further controlled to provide adequate flexibility and glass transition temperature for the polyamide formed to increase processability ² C which may be straight chain ₄ -C ₁₂ Alkylene group, or C having at most two branches ₄ -C ₁₂ Alkylene group, and the carbon number of the two branches is less than or equal to 3, or more preferably C which can be a straight chain ₂ -C ₈ Alkylene group, or C having at most two branches ₂ -C ₈ Alkylene groups, and the carbon numbers of the two branched chains are integers less than or equal to 3 respectively.

[ third repeating Unit ]

Ar in formula (III) may be C ₆ -C ₁₈ An arylidene group. In some embodiments, there may also be atoms other than carbon and hydrogen in Ar, i.e., the arylene group may have other substituents. For example, the arylene group can have C therein ₁ -C ₈ Alkoxy (alkoxy group), halogen atom (ha)logen atom), sulfonic acid group (sulfonic group), or ether group (ethergroup). In some embodiments, formula (III) can be

/>

And the like. Since the third repeating unit has an aromatic group, the third repeating unit can further improve the mechanical strength of the polyamide formed therefrom, and since the third repeating unit is not a long chain unit, the crystallinity of the polyamide formed is not excessively improved.

In some embodiments, to control the length of the third repeat unit for better mechanical strength of the polyamide, ar can be C ₆ -C ₁₀ An arylidene group. In some embodiments, to provide a polyamide with a better degree of polymerization, the carbonyl (-CO-) in formula (III) is not on the adjacent carbon of the aromatic ring to reduce the formation of imide (imide) that interrupts the polymerization reaction. In some embodiments, the aromatic ring in formula (III) has a branch with a carbonyl group (-CO-) on it, the carbon number of which is an integer less than or equal to 3. For example, when formula (III) is

In the case, the aromatic ring has a branched chain of carbonyl (-CO-) and the number of carbon atoms is 2. When the aromatic ring in the formula (III) has a branch having a carbonyl group (-CO-) and the number of carbons is an integer of 3 or less, the resulting polyamide polymer has appropriate flexibility and glass transition temperature.

[ fourth repeating Unit ]

/>

In order to disrupt the crystalline structure of the polyamide formed, R3 in formula (IV) may be

Or C having at least three branches ₇ -C ₂₅ An alkylene group. By the structures in the formed polyamide, the polyamide molecular chains cannot be orderly arranged, so that the crystal size is reduced, the scattering of visible light is reduced, and the light transmittance of the visible light is improved.

In some embodiments, R ³ (may be)

Which is linked in the asterisk position to-NH-in formula (IV), R ⁴ And R ⁵ Independently a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms, and R ⁴ And R ⁵ Are different. When R is ⁴ Or R ⁵ And (3) a single bond, namely, a-NH-in the formula (IV) is directly connected with a naphthenic structure. n may be an integer of 0 to 10, R ⁶ C which may be or may independently be straight chain, or branched ₁ -C ₃ An alkyl group. m may be an integer of 0 to 7. In some embodiments, the size of the cycloalkane and the number of branches on the cycloalkane can be reduced to provide better reactivity between the repeating unit and other repeating units, e.g., m can be an integer from 1 to 3, n can be an integer from 3 to 5; or reducing the length of a substituent on the cycloalkane, e.g. substituent R on the cycloalkane ⁶ Has a carbon number of R or less ⁴ (at this time R ⁴ ＜R ⁵ ) (ii) a Or reducing steric hindrance of the two amino groups on the cycloalkane (steric hindrance), e.g. by reacting R with ⁴ And R ⁵ Not on the same carbon, or by making R ⁴ And R ⁵ Not on adjacent carbons.

In some embodiments, R ³ (may be)

When R is ³ Is composed of

When formula (IV) is an asymmetric cyclic diamine unit. The term "asymmetric" as used herein means (1) based on ` or ` based on `>

Has a main structure of cycloalkane, so that->

The whole body is a non-planar structure; (2) Due to R ⁴ Is not equal to R ⁵ The carbon chain numbers of the two amino groups in the formula (IV) are different.

In some embodiments, R ³ Or C having at least three branches ₇ -C ₂₅ Alkylene group, more preferably C having at least three branches ₇ -C ₁₅ An alkylene group. R as defined herein ³ The term "branched chain" refers to a branched carbon chain having a side chain on the main chain formed by the two carbon atoms connected from the beginning to the end. In some embodiments, R ³ (may be)

And the like, which are respectively linked to-NH-in formula (IV) at the asterisk position. In some embodiments, the branch C does not unduly affect the mechanical strength and reactivity with other units of the polyamide formed ₇ -C ₂₅ The number of branches of the alkylene group may be 10 or less, and/or the number of carbons of the branches may be 5 or less.

When (IV) is an asymmetric cyclic diamine unit or a diamine unit having at least three branched chains, the polyamide molecular chains are not regularly arranged with each other, so that large-sized crystals or crystal regions are not easily formed, scattering of visible light can be reduced, and polyamide having high visible light transmittance can be obtained. The first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit are matched, so that the polyamide with the repeating units has proper mechanical strength and transparency.

The polyamide having the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit described herein can be obtained by condensation polymerization of a diacid (or an ester, an acid anhydride or an acid halide which can generate a diacid corresponding to a repeating unit) corresponding to each repeating unit and a diamine compound in any suitable manner. For example, the diacid corresponding to the first repeat unit can be of the formula R ¹ (COOH) ₂ The diamine corresponding to the second repeating unit may have the general formula R ² (NH ₂ ) ₂ The diacid corresponding to the third repeating unit can be of the general formula Ar (COOH) ₂ The general formula of the diamine corresponding to the fourth repeating unit can be R ³ (NH ₂ ) ₂ . The polyamide is obtained by, for example, melt polymerization (the reaction temperature is higher than the melt temperature of the product polymer), solution polymerization, or the like using the above-mentioned compound as a starting material. In some embodiments, when condensation polymerization is to be carried out between the reactants, a suitable catalyst may be added, such as a suitable agent, for example, sodium dihydrogen phosphate, stannous chloride, or dibutyltin dilaurate.

In some embodiments, the diacid compound and the diamine compound corresponding to the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit can be directly mixed to perform one-pot synthesis. Or reacting the diacid and the diamine compounds corresponding to the first repeating unit and the second repeating unit, reacting the diacid and the diamine compounds corresponding to the third repeating unit and the fourth repeating unit, and reacting the obtained products to obtain the polyamide with the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit. Or, the diacid and diamine compounds corresponding to the first repeating unit and the fourth repeating unit are reacted first, the diamine and diacid compounds corresponding to the second repeating unit and the third repeating unit are reacted, and the products are reacted to obtain the polyamide.

In some embodiments, the molar ratio a: b between the first repeating unit and the second repeating unit in the present polyamide can be 1.1:1 to 1:1.1, and more preferably can be 1.01: 1 to 1: 1.01. The molar ratio c: d between the third repeating unit and the fourth repeating unit may be 1.1:1 to 1:1.1, and more preferably 1.01: 1 to 1: 1.01. When the difference in the molar ratio between the first repeating unit and the second repeating unit and/or the molar ratio between the third repeating unit and the fourth repeating unit is too large, it means that the overall mechanical properties may be adversely affected by an excessive amount of the monomers in the polyamide to be formed, and therefore, the diamine and the dicarboxylic acid may be in an equimolar ratio at the stage of synthesizing the polyamide. In some embodiments, the ratio of the sum of the weights of the first repeating unit and the second repeating unit, and the sum of the weights of the third repeating unit and the fourth repeating unit in the polyamide is from 1:2 to 2.5:1, and more preferably from 1:1 to 2: 1. When the weight and ratio of the first repeating unit to the second repeating unit in the polyamide are too high, crystallinity rises, affecting optical transparency; when the weight and ratio of the first repeating unit to the second repeating unit in the polyamide are too low, ductility is reduced, and the polymer is too brittle to affect mechanical properties.

In some embodiments, the polyamides of the present disclosure can have a number-average molecular weight (Mn) of 5,000 to 20,000. If the molecular weight of the polyamide is too low, it may result in deterioration of mechanical properties (for example, the plastic body is too brittle, the elongation at break is lowered, etc.). When the molecular weight is too high, plastic working is not easily performed. In addition, the polyamide described herein has the first repeating unit, the second repeating unit, the third repeating unit, and the fourth repeating unit, so that the polyamide can have smaller crystal grains and/or lower crystallinity, for example, the crystallinity of the polyamide can be only 25% to 50%, and more preferably 30% to 50%. In some embodiments, the polyamide of the present disclosure has a transmittance of 80% or more, preferably 85% or more, in the visible wavelength range (400 nm to 800 nm). In some embodiments, the tensile strength of the polyamides of the present disclosure (A)tensile strength) can be 1,600-2,000kg/cm ² The percent elongation at failure (percent elongation) may be from 7.0 to 10.0 percent and the modulus of tortuosity (elastic modulus) may be from 84,000 to 9,3000kg/cm ² 。

In accordance with other embodiments, the present disclosure further provides a chain extended polyamide. In some embodiments, the chain-extended polyamide may be formed from the aforementioned polyamide with the addition of a suitable chain extender. The molecular weight of the chain-extended polyamide is greatly improved, so that the material with high transparency, high melting point and high mechanical strength is obtained.

In some embodiments, three or more functional groups (e.g., amino (-NH) groups) that can form bonds with units in the polyamide may be used to crosslink the polyamides to form a network structure ₂ ) Or a carboxylic machine (-COOH)) as a chain extender. For example, the chain extender may be a triamine, a tetraamine, a tricarboxylic acid, or a tetracarboxylic acid. In some embodiments, the chain extender may further contain other functional groups without unduly affecting the progress of the crosslinking reaction. For example, the chain extender may contain a hydroxyl group (-OH), a halogen (halogen), an alkoxy group (alkoxy group), or the like. In some embodiments, the chain extender may be trimesic acid (benzene-1, 3,5-tricarboxylic acid), tricarballylic acid (Propane-1, 2,3-tricarboxylic acid), citric acid (2-hydroxypropane-1, 2,3-tricarboxylic acid), pyromellitic acid (pyromelitic acid), 3', 5' -biphenyltetracarboxylic acid (bipheny 1-3,3', 5' -tetracarboxylic acid), 1,3,5, 7-octanetetracarboxylic acid (octanetane-1, 3,5,7-tetracarboxylic acid), triaminebenzene (benzeamine), or 1,2,4,5-benzenetetramine (1, 2,4, 5-benzanetetramine), and the like.

According to some embodiments, when the chain extender is a tricarboxylic acid or a tetracarboxylic acid, the formed chain-extended polyamide further comprises a fifth repeating unit represented by formula (V) or formula (VI) in addition to the previously described first repeating unit of formula (I), the second repeating unit of formula (II), the third repeating unit of formula (III), and the fourth repeating unit of formula (IV),

wherein, the carbonyl end (-CO-) in the fifth repeating unit is connected with the amino end (-NH-) in the formula (II) or the formula (IV) in the position of a mark. R in the formula (V) ⁸ Is C ₆ -C ₁₈ Aromatic, or straight, branched or cyclic C ₃ -C ₁₅ Saturated aliphatic, wherein a carbonyl group (-CO-) in formula (V) or formula (IV) each replaces the C ₆ -C ₁₈ H on any carbon of aromatic series or C is substituted on each ₃ -C ₁₅ H on any carbon of the saturated aliphatic. In some embodiments, R ⁸ Any of the H's on any carbon in (a) may be further substituted with other functional groups, for example 1 to 3H's. For example, the functional group can be hydroxyl (-OH), halogen (halogen), or C ₁ -C ₅ Alkoxy (alkoxy group), and the like.

In order to provide suitable mechanical strength to the formed chain-extended polyamide, in some embodiments, R in formula (V) ⁸ Is C ₆ -C ₁₀ Aromatic, or straight, branched or cyclic C ₃ -C ₈ Saturated aliphatic, wherein the C is substituted by a carbonyl group (-CO-) in the formula (V) or the formula (IV) ₆ -C ₁₀ H on any carbon of aromatic series or C is substituted on each ₃ -C ₈ H on any carbon of the saturated aliphatic. In some embodiments, R ⁸ Any of the H's on any carbon in (a) may be further substituted with other functional groups, for example 1 to 3H's. For example, the functional group can be hydroxyl (-OH), halogen (halogen), or C ₁ -C ₅ Alkoxy (alkoxy group), and the like.

In some embodiments, to form a chain-extended polyamide having a fifth repeat unit as shown in formula (V) or formula (VI), the chain extender may be C ₉ -C ₂₁ Aromatic tribasic acid, C ₁₀ -C ₂₂ Aromatic tetrabasic acid, C ₆ -C ₁₈ Saturated aliphatic tribasic acids, or C ₇ -C ₁₉ Saturated aliphatic tetrabasic acids. In some embodiments, the chain extender may be C ₉ -C ₁₃ Aromatic tribasic acid, C ₁₀ -C ₁₄ Aromatic tetrabasic acid, C ₆ -C ₁₁ Saturated aliphatic tribasic acids, or C ₇ -C ₁₂ Saturated aliphatic tetrabasic acids.

In some embodiments, the fifth repeat unit comprises from 1wt% to 5.0wt%, and more preferably from 1.5wt% to 3.0wt%, of the total weight of the chain-extended polyamide. When the content of the fifth repeating unit is too high, the chain-extended polyamide formed by the fifth repeating unit is excessively embrittled; when the content of the fifth repeating unit is too low, the resulting chain-extended polyamide may not obtain a suitable mechanical strength.

In some embodiments, the chain-extended polyamide can be formed by combining the corresponding monomers (e.g., R) of the first repeat unit ¹ (COOH) ₂ ) The corresponding monomer of the second repeating unit (e.g. R) ² (NH ₂ ) ₂ ) The corresponding monomer of the third repeating unit (e.g., ar (COOH)) ₂ ) The corresponding monomer of the fourth repeating unit (e.g., R) ³ (NH ₂ ) ₂ ) And the corresponding monomer of the fifth repeating unit (e.g., R) ⁸ (COOH) ₃ Or R ⁸ (COOH) ₄ ) Directly reacting to obtain the product.

In yet other embodiments, the polyamide may be formed first and then the chain extender added to form the chain extended polyamide, as previously described. Due to the chain-extended polyamide formed after the chain extender is added, the molecular weight of the chain-extended polyamide is greatly increased compared with the original polyamide. The high molecular weight chain-extended polyamide thus has high mechanical strength and an extremely high melting point, but also makes it less workable (for subsequent processing in conventional processing of non-ferrous metals, such as by lathes, milling machines, planers, drills, etc., to the desired workpiece shape/size). By forming the lower melting polyamide first, it can be formed in a molten state if a suitable temperature is provided (e.g., heated above 250 ℃ below the cracking temperature of the polyamide) and can be shaped using, for example, a mold. After shaping, adding a chain extender for reaction, and gradually increasing the melting point with the increase of the molecular weight to form a solid state (at this time, the solid-phase polycondensation is considered to be carried out, and the reaction temperature can be set to be higher than the glass transition temperature of the polymer but lower than the melt temperature of the polymer). Thus, the chain-extended polyamide product having a desired shape can be obtained without additional excessive machining or the like.

In some embodiments, the present chain-extended polyamide also has first through fourth repeating units, and thus also has smaller grains, and/or lower crystallinity, for example, the crystallinity of the chain-extended polyamide may be only 25% to 50%, and more preferably 30% to 50%. The transmittance of the material can be more than 75%, preferably more than 80% in the visible light wavelength range (400 nm to 800 nm). The chain-extended polyamides also have a relatively high glass transition temperature, which may be, for example, from 120 ℃ to 250 ℃. In some embodiments, the present chain-extended polyamides may have a tensile strength (tensile strength) of 1,500 to 2,500kg/cm ² More preferably 1,700-2,200kg/cm ² (ii) a The breaking elongation (percent elongation) can be 1-10%, preferably 3-8%; the flexural modulus (elastic modulus) may be 50,000 to 150,000, more preferably 60,000 to 120,000kg/cm ² . The chain-extended polyamide is shown to have high visible light transparency and higher mechanical strength compared with polyamide, so that the chain-extended polyamide can be applied to more different fields or applications.

In order to make the aforementioned and other objects, features, and advantages of the present disclosure more comprehensible, several embodiments and comparative examples are described in detail below without limiting the present disclosure.

Example 1 preparation of Polyamide 1

First, an intermediate a containing a first repeating unit and a second repeating unit is prepared. 7.307g (0.05 mol) of adipic acid (to provide the first repeat unit) were weighed out into a 250mL Erlenmeyer flask containing 50mL of ethanol, and the adipic acid was dissolved by placing the Erlenmeyer flask into a water bath at 60 ℃. Another 5.811g (0.05 mol) of hexamethylenediamine (to provide the second repeat unit) is weighed out and placed in a further 250mL Erlenmeyer flask with 60mL of ethanol, and the hexamethylenediamine is dissolved in a water bath at 60 ℃. Then, an alcohol solution of hexamethylenediamine was poured into an alcohol solution of adipic acid, and the flask was shaken to react the mixture, whereby the amide salt formed was precipitated. And (3) filtering the generated amide salt when the reaction system in the bottle does not release heat any more, and drying in a vacuum drying oven at 40 ℃ to obtain an intermediate A.

In addition, an intermediate B containing a third repeating unit and a fourth repeating unit was prepared. 7.307g (0.05 mol) of isophthalic acid (to provide a third repeat unit) were weighed into a 250mL Erlenmeyer flask containing 50mL of alcohol, and the Erlenmeyer flask was placed in a water bath at 60 ℃ to dissolve the isophthalic acid. In addition, 7.915g (0.05 mol) of 2, 4-trimethylhexamethylenediamine (I) are weighed out

To provide a fourth repeat unit), placed in another 250mL Erlenmeyer flask containing 60mL of alcohol, and placed in a water bath at 60 ℃ to dissolve 2, 4-trimethylhexamethylenediamine. Then, an alcohol solution of 2, 4-trimethylhexamethylenediamine was poured into an alcohol solution of isophthalic acid, and the resulting amide salt was precipitated by shaking the flask to react. And (3) filtering the generated amide salt when the reaction system in the bottle does not release heat any more, and drying in a vacuum drying oven at 40 ℃ to obtain an intermediate B.

Thereafter, intermediate A was reacted with intermediate B to obtain polyamide 1. 2.0 g of intermediate A,1.0 g of intermediate B were added sequentially to a test tube followed by 2 drops of sodium dihydrogen phosphate at a concentration of 0.075g/mL and 1 drop of stannous chloride solution at a concentration of 0.075 g/mL. The test tube is evacuated to a vacuum of between-0.095 and-0.100 MPa and then heated to 200 ℃. At this time, the reactants in the test tube began to melt and react, and water vapor was evolved. The exothermic heat of reaction makes the temperature of the whole reaction system continuously rise until the reactants are molten. After the temperature was stabilized, the reaction mixture was held at 200 ℃ for 30 minutes, and then the reaction mixture was slowly cooled to room temperature (about 23 to 27 ℃ C.), and the product was taken out to obtain 3.0 g of polyamide 1.

Example 1 '-chain-extended Polyamide 1' ]

3.0 g of the polyamide 1 obtained in example 1 was placed in a heatable mold, the temperature was set to 270 ℃ for about 30 minutes, 0.05 g of trimesic acid was added, the temperature was again maintained at 270 ℃ for about 1 hour, and then slowly cooled to room temperature to obtain a chain-extended polyamide 1'.

Example 2 preparation of Polyamide 2

Intermediate A and intermediate B were prepared in substantially the same manner as in example 1, except that the compound providing the fourth repeating unit in intermediate B was 8.512g (0.05 mol) of isophoronediamine

The polyamide 2 obtained by reacting the intermediate A with the intermediate B was also prepared in substantially the same manner as in example 1, except that the intermediate A was 1.0 g, the intermediate B was 1.5 g, and the test tube was heated to 210 ℃. 2.5 g of polyamide 2 are then obtained.

Example 2 '-preparation of chain-extended Polyamide 2'

2.5 g of the polyamide 2 obtained in example 2 (assuming that all of the previous reaction was carried out as in example 1) was placed in a heatable mold, the temperature was set to 280 ℃ for about 3 minutes, 0.05 g of trimesic acid was added, the temperature was again maintained at 280 ℃ for about 1 hour, and then the mixture was slowly cooled to room temperature to obtain chain-extended polyamide 2'.

Example 3 preparation of Polyamide 3

Intermediate A was prepared in substantially the same manner as in example 1 except that the compound providing the fourth repeating unit in intermediate B was 9.90g (0.05 mol) of 1-amino-3-aminoethyl-3-methylcyclodecane

The polyamide 3 obtained by reacting the intermediate A with the intermediate B was also prepared in substantially the same manner as in example 1, except that the intermediate A was 2.0 g, the intermediate B was 1.0 g, and the test tube was heated to 200 ℃. 3.0 g of polyamide 2 are then obtained.

Example 3 '-preparation of chain-extended Polyamide 3' ]

3.0 g of the polyamide 3 obtained in example 3 was placed in a heatable mold, the temperature was set to 270 ℃ for about 3 minutes, 0.05 g of trimesic acid was added, the temperature was again maintained at 270 ℃ for about 1 hour, and then the mixture was slowly cooled to room temperature to obtain a chain-extended polyamide 3'.

Example 4 preparation of Polyamide 4

Intermediate A was prepared in substantially the same manner as intermediate B in example 1, except that 10.0g (0.05 mol) of the compound providing the fourth repeating unit in intermediate B was 4,5, 6-trimethyl-1, 9-nonanediamine

The polyamide 3 obtained by reacting the intermediate A with the intermediate B was also prepared in substantially the same manner as in example 1, except that the intermediate A was 2.0 g, the intermediate B was 1.0 g, and the test tube was heated to 200 ℃. 3.0 g of polyamide 4 are then obtained.

Example 4 '-preparation of chain-extended Polyamide 4' ]

3.0 g of the polyamide 4 obtained in example 3 was placed in a heatable mold, the temperature was set to 270 ℃ for about 3 minutes, 0.05 g of trimesic acid was added, the temperature was again maintained at 270 ℃ for about 1 hour, and then the mixture was slowly cooled to room temperature to obtain chain-extended polyamide 4'.

Comparative example 1-Polyamide C1 having Only first repeating Unit and second repeating Unit

The procedure was substantially the same as in example 1, except that the intermediate A alone was synthesized without synthesizing the intermediate B, and that the reactant adipic acid of the intermediate A was 14.61 g (0.1 mol), the amount of hexamethylenediamine was 11.62 g (0.1 mol), and the amount of solvent for dissolving hexamethylenediamine was changed to 120ml of alcohol. Intermediate A is obtained after the reaction.

3 g of intermediate A were then introduced into a test tube, the procedure being as in example 1, except that the tube was heated to 210 ℃. 3.0 g of polyamide C1 are obtained.

Comparative example 1 '-chain-extended Polyamide C1')

3.0 g of the polyamide C1 obtained in comparative example 1 was placed in a heatable mold, the temperature was set to 260 ℃ for about 30 minutes, 0.05 g of trimesic acid was added, the temperature was again maintained at 260 ℃ for about 1 hour, and then, the mixture was slowly cooled to room temperature to obtain a chain-extended polyamide C1'.

Comparative example 2-Polyamide C2 having Only third repeating Unit and fourth repeating Unit

The procedure was substantially the same as in example 1, except that intermediate A was not synthesized and only intermediate B was synthesized, and that the intermediate B reactant isophthalic acid was 16.614 g (0.1 mol), isophorone diamine was 13.821 g (0.1 mol), and the amount of solvent dissolving isophorone diamine was changed to 120ml of alcohol. Intermediate B is obtained after the reaction.

3 g of intermediate A were then introduced into a test tube, the procedure being as in example 1, except that the tube was heated to 210 ℃. 3.0 g of polyamide C2 are obtained.

Comparative example 2 '-chain-extended Polyamide C2')

3.0 g of the polyamide C1 obtained in comparative example 2 was placed in a heatable mold, the temperature was set to 260 ℃ for about 30 minutes, 0.05 g of trimesic acid was added, the temperature was again maintained at 260 ℃ for about 1 hour, and then, the mixture was slowly cooled to room temperature to obtain a chain-extended polyamide C2'.

The preparation conditions of the above examples and comparative examples are summarized in the following Table 1.

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The polyamides prepared in the foregoing examples and comparative examples and the chain-extended polyamides were subjected to measurement of light transmittance, crystallinity, tensile strength, elongation at break, flexural modulus, number average molecular weight, and glass transition temperature, respectively.

[ light transmittance ]

The transmittance of visible light having a wavelength of 380 nm was measured by using a UV-visible-near infrared spectrophotometer (PerkinElmer, lambda 35).

[ degree of crystallinity ]

Obtained using a reflection-type X-ray diffractometer (philippi electronics, mahwah, n.j., cat.no. pw1075/00) at a scanning speed of 1 ° (2 θ) per minute; incremental stepwise changes of 0.025 ° (2 θ); the pulse height analysis method is "Differential"; the measurement is performed in a scanning range of 6 ° to 38 ° (2 θ).

The crystallinity can be expressed as the Crystalline Perfection Index (CPI) (in terms of p.f. disorder and w.o. statton, j.polym.sci.part C, no.13, pp.133-148, 1966). As the crystallinity increases, the position of the two peaks at 21 ° and 23 ° (2 θ) will change, with the peaks moving further closer to the theoretical corresponding positions of the Bunn-Garner type nylon 66 structure. This change in peak position can be used to measure the crystallization completion index of nylon 66.

Where d (surface) and d (interior) are the Bragg'd' spacing, the peaks are at 23 ° and 21 °, respectively, and the denominator 0.189 is the d (100)/d (010) value for perfect nylon 66 crystallization (as reported by Bunn and Garner in proc. Royal soc. (London), a189, 39, 1947).

[ grain size ]

The full width at half height maximum (full width at half maximum) of the equatorial diffraction peak 2 θ value of 20 ° to 21 ° was measured using a reflection type W-ray diffractometer (philippi electronic instrument, mahwah, n.j., cat.no. pw1075/00).

Apparent grain size (ACS) = (K λ)/(β COS θ), where the constant K is taken to be 1 (unity) and λ is the X-ray wavelength (here, unity)

) (ii) a Beta is the half-height width of the diffraction peak; theta is half the Bragg angle (obtained from the diffraction pattern, i.e. half the 2 theta value of the selected peak).

[ tensile Strength ]/[ elongation at failure ]

The measurement was carried out by using an Shimadzu oil pressure type universal tester UH-X according to ISO 527 standard. The sample is a dumbbell sample in the shape of 1B defined in the specification, and is stretched at the speed of 1mm/min until the sample is broken, and the stress value and the elongation rate of the sample at the break are recorded.

[ flexural modulus ]

The Shimadzu oil pressure universal tester UH-X adopts ISO 178 standard. The sample is a 4mmx10mmx80mm strip, and the sample is placed on two fixed supporting points (fixed anchors) at a certain distance during the test, then the sample is pressed from top to bottom at the midpoint of the two supporting points by a speed of 15mm/min (three-point test method) until the sample is broken, and the stress value is recorded.

[ number average molecular weight ]

Measurement was performed by Gel Permeation Chromatography (GPC) using Shodex GPC SYSTEM-II manufactured by Shodex and electrician. Solvent Using Hexafluoroisopropanol (HFIP), a 10mg sample of the polyamide resin was placed over 10g of HFIP and stirred overnight, and the sample was used for the measurement. The conditions for the measurement were: the test column used 2 GPC standard columns (column specification 300X8.0mm I.D.) HFIP-806M manufactured by the same company, and the reference column used 2 HFIP-800, the column temperature was 40 ℃ and the solvent flow rate was 1.0min. The number average molecular weight of the standard sample was determined using methyl acrylate (PMMA) and SIC-480II manufactured by the same company as the data processing software.

[ glass transition temperature ]

Thermal analysis was performed with a Differential Scanning Calorimetry (DSC) (TAInstruments, DSC Q100) at a temperature rise rate of 10 ℃/min. The intersection of the line drawn by the baseline in the endothermic curve and the maximum slope obtained during heating is the glass transition temperature (Tg, ° c).

The data obtained for the polyamides obtained in the examples and comparative examples and for the chain-extended polyamides are collated in Table 2 below.

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The polyamides of examples 1-4 and the chain-extended polyamides of examples 1'-4' all have suitable mechanical strength, in addition to high light transmittance. On the other hand, it is understood from comparative examples 1 and examples 1 to 4, and comparative examples 1' and examples 1' to 4' that the polyamide C1 of comparative example 1 and the chain-extended polyamide C1' of comparative example 1' have only a relatively low light transmittance because the crystal grain size and crystallinity thereof are greatly increased and a large amount of visible light is scattered when the third repeating unit and the fourth repeating unit are absent from the polymer.

When only the third repeating unit and the fourth repeating unit are contained in the polyamide (e.g., comparative examples 2 and 2 '), it can be found that the polyamide has a lower grain size and a good transmittance, but the physical and mechanical properties (e.g., elongation at break, flexural modulus) of the polyamide are inferior to those of examples 1 to 4 and examples 1' to 4', and thus cannot meet the needs of the industry.

As can be seen from examples 1 and 2, and examples 1 and 2', when a long-chain diamine unit having at least three branches or an asymmetric cyclic diamine unit is used as the fourth repeating unit, the obtained polyamide or chain-extended polyamide has low crystallinity, a small crystal grain size, and high visible light transmittance.

As shown in examples 3 and 3 'and examples 4 and 4', even if a larger ring of asymmetric cyclic diamine units or a longer chain of long-chain diamine units is used as the fourth repeating unit, the resulting polyamide or chain-extended polyamide can still have a certain visible light transmittance.

Although the embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure. Moreover, the scope of the present disclosure is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Accordingly, the scope of the present disclosure includes the processes, machines, manufacture, compositions of matter, means, methods, and steps described above. In addition, from the above-mentioned embodiments, those skilled in the art can understand that the present invention can be applied to various embodiments. Each claim also constitutes a separate embodiment, and the scope of the present disclosure also includes combinations of each claim and embodiment. The scope of the present disclosure should be determined with reference to the appended claims.

Claims

1. A polyamide comprising a first repeat unit of formula (I), a second repeat unit of formula (II), a third repeat unit of formula (III), and a fourth repeat unit of formula (IV):

wherein the first repeating unit, the second repeating unit, the third repeating unit and the fourth repeating unit are arranged randomly, in a block manner or alternately, and a carbonyl terminal (-CO-) in the formula (I) and the formula (III) is connected with an amino terminal (-NH-) in the formula (II) or the formula (IV);

wherein R is ¹ Is straight-chain, branched or cyclic C ₂ -C ₁₅ An alkylene group;

R ² is a straight chain C ₂ -C ₁₅ Alkylene group, or C having at most two branches ₂ -C ₁₅ Alkylene groups, wherein the carbon numbers of the two branched chains are integers less than or equal to 3;

ar is C ₆ -C ₁₈ An arylene group;

wherein the monomer forming the fourth repeating unit of formula (IV) is 1-amino-3-aminoethyl-3-methylcyclodecane or 4,5, 6-trimethyl-1, 9-nonanediamine.

2. The polyamide of claim 1, wherein:

R ¹ is a straight chain or branched C ₄ -C ₁₂ An alkylene group;

R ² is a straight chain C ₄ -C ₁₂ Alkylene group, or C having at most two branches ₄ -C ₁₂ Alkylene group, and the carbon number of the two branched chains is less than or equal to 3;

ar is C ₆ -C ₁₀ An arylene group.

3. The polyamide according to claim 1, wherein the molar ratio of the first repeating unit to the second repeating unit a: b is 1.1:1 to 1:1.1, molar ratio c between the third repeating unit and the fourth repeating unit: d is 1.1:1 to 1:1.1.

4. the polyamide of claim 1, wherein the ratio of the sum of the weights of the first repeating unit and the second repeating unit to the sum of the weights of the third repeating unit and the fourth repeating unit is 1:2 to 2.5:1.

5. the polyamide according to claim 1, having a number-average molecular weight (Mn) of 5,000 to 20,000.

6. The polyamide according to claim 1, further comprising a fifth repeating unit represented by formula (V) or formula (VI),

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the position of a carbonyl end (-CO-). In the fifth repeating unit is connected with an amino end (-NH-) in the formula (II) or the formula (IV); r in the formula (V) ⁸ Is C ₆ -C ₁₈ Aromatic, or straight, branched or cyclic C ₃ -C ₁₅ Saturated aliphatic.

7. The polyamide according to claim 6, wherein the fifth recurring unit is present in an amount of 1wt% to 5wt% based on the total weight of the polyamide.

8. The polyamide of claim 6, wherein the ratio of the sum of the weights of the first repeating unit and the second repeating unit to the sum of the weights of the third repeating unit and the fourth repeating unit is 1:2 to 2.5:1.

9. the polyamide according to claim 6, having a glass transition temperature (Tg) of 120 ℃ to 250 ℃.

10. The polyamide according to claim 6, having a light transmittance of 75% to 100% and a crystallinity of 25% to 50%.

11. The polyamide as claimed in claim 6, which has a tensile strength of 1,500 to 2,500kg/cm ² The breaking elongation is 1-10%, and the flexural modulus is 50,000-150,000kg/cm ² 。

12. A process for making the polyamide of claim 6, comprising:

(a) Providing the polyamide of claim 1; and

(b) In the polyamide, C is added ₉ -C ₂₁ Aromatic tribasic acid, C ₁₀ -C ₂₂ Aromatic tetrabasic acid, C ₅ -C ₁₈ Saturated aliphatic tribasic acid, or C ₆ -C ₁₉ Saturated aliphatic tetrabasic acid to react.

13. The method of claim 12, wherein step (a) further comprises heating the polyamide to a temperature above 250 ℃ and below the cracking temperature of the polyamide, and then performing step (b).

14. The method for producing polyamide as claimed in claim 12, wherein said C is ₉ -C ₂₁ Aromatic tribasic acid, C ₁₀ -C ₂₂ Aromatic tetrabasic acid, C ₅ -C ₁₈ Saturated aliphatic tribasic acids, or C ₆ -C ₁₉ The addition amount of the saturated aliphatic tetrabasic acid is 1 to 5 weight percent of the weight of the polyamide.