JPS59230016A - Production of acetal polymer - Google Patents

Abstract

PURPOSE:To obtain a polyacetal having arbitrarily controllable molecular weight and excellent fluidity and impact resistance, by carrying out the anionic polymerization of formaldehyde in the presence of a polyfunctional compound containing >=2 kinds of >=3 functional groups selected from hydroxyl group, carboxyl group and amino group. CONSTITUTION:The objective polyacetal is obtained by the anionic polymerization of formaldehyde usually in an organic medium (e.g. n-hexane) in the presence of a polyfunctional compound containing >=2 kinds of >=3 functional groups selected from hydroxyl group, carboxyl group and amino groups (preferably 2- carboxyl-1,4-butanediol, 2-amino-1,4-butanediol, 2-aminoadipic acid, 2-amino-4- hydroxybenzoic acid, etc.) as a molecular weight regulator, and is necessary, in the presence of a polymerization catalyst (e.g. dibutyltin dimethoxide). The polymerization is carried out e.g. by blow polymerization, solution polymerization, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for making acetal polymers having desired molecular weights and improved rheological and impact properties. More specifically, hydroxyl group and Cal are groups containing at least two types of functional groups selected from the group consisting of xyl group and amino group.
The present invention relates to a method for obtaining an acetal polymer having excellent fluidity and impact properties by polymerizing formaldehyde using a polyfunctional compound containing at least 100% polyfunctional compound as a molecular weight regulator.

Japanese Patent Publication No. 35-9435 states that the molecular weight of the cyformaldehyde polymer is determined by the amounts of trace amounts of water, methanol, and formic acid present in the polymerization system.

Further, in U.S. Pat. No. 30173°89, there is a description that formaldehyde is polymerized in the presence of a chain transfer agent such as a monoester, monoalcohol, acid anhydride, amide, or imide, and an anionic initiator. There is. Among the chain transfer agents found in these publications, compounds with so-called active hydrogen have a sufficiently fast chain transfer rate, but compounds without active hydrogen such as monoesters, acid anhydrides, amides, imides, etc. Disadvantages include slow migration speed and insufficient control of molecular weight. Furthermore, the fluidity and impact properties of polymers produced using these compounds, including monoalcohols, as chain transfer agents are insufficient, and there is a large room for improvement.

In Japanese Patent Application Laid-open No. 49-4786, -〇〇〇)I
It is described that a monomeric organic compound having two 10H groups in one molecule is added as a chain transfer agent to polymerize formaldehyde. Although it is possible to control the molecular weight with this method, the flow and impact properties of the resulting polymer are poor.

On the other hand, in Japanese Patent Publication No. 44-23341, in the presence of a polyhydroxy compound using a cationic polymerization catalyst,
There is a description that trioxane or formaldehyde is polymerized. During polymerization using a cationic polymerization catalyst, a main chain scission reaction called noidolide shift reaction occurs, resulting in a decrease in the molecular weight of the polymer. The main chain scission reaction is particularly noticeable in the polymerization of formaldehyde, and when a cationic polymerization catalyst is used, it is extremely difficult to obtain a formaldehy r polymer having a sufficiently high molecular weight.

Japanese Patent Laid-Open No. 56-98219 discloses a method of anionically polymerizing formaldehyde in the coexistence of a polyhydric alcohol of triol or higher.

Acetal polymers are widely used as thermoplastic engineering plastics, usually by injection molding,
Shaped using a molding method such as extrusion molding. Improving the flow and impact properties of acetal polymers
- There are great expectations that this will greatly open up new uses for polymers.

As a result of extensive studies on methods for controlling the molecular weight of acetals and polymers, the present inventors have determined that at least two types of functional groups selected from the group consisting of hydroxyl groups, carxyl groups, and amine groups are
The present invention was completed based on the discovery that a polyfunctional compound containing more than 100% of polyfunctional compounds functions as a good molecular weight regulator, and that the resulting nonapolymer has good fluidity and impact properties.

That is, the present invention provides at least two types of functional groups selected from the group consisting of hydroxyl group, carboxylic group, and amine group.
This is a method for producing a polyacetal polymer in which formaldehyde is polymerized using an anionic polymerization catalyst in the presence of a polyfunctional compound containing at least 100% of polyfunctional compounds.

When formaldehyde is polymerized in the coexistence of a polyfunctional compound, chain transfer and chain branching occur, thereby controlling the molecular weight of the polymer. The branched polymers still produced exhibit improved flow and impact properties.

Chain branching of the acetal polymer occurs only when a polyfunctional compound containing three or more functional groups of at least two types selected from the group consisting of hydroxyl group, carboxylic group, and amino group is used. (When a compound having one or two hydroxyl groups, carxyl groups, or amine groups is used, chain transfer occurs, but chain branching does not occur.) The present invention will be specifically explained below.

In the present invention, a polyfunctional compound containing three or more functional groups of at least two types selected from the group consisting of a hydroxyl group, a carxyl group, and an amino group is used as a molecular weight regulator in formaldehyde.

Here, there are four combinations of functional groups in one molecule: a hydroxyl group and a carxyl group, a hydroxyl group and an amine group, a carxyl group and an amino group, and a hydroxyl group/carxyl group and an amino group.

The first group of polyfunctional compounds are compounds containing three or more hydroxyl groups and carboxylic groups in one molecule.

This group includes, for example, 2-carxyl-1,4-
Sothanediol, trimethylolzolonodenadipic acid adduct (contains 2 hydroxyl groups and 1 cardixyl group), glycerincono-phosphate adduct (contains 11 hydroxyl groups and 2 cardicyl groups), pentaerythritol malonic acid adduct ( (3 hydroxyl groups, 1 carfuxyl group), tartaric acid, p-hyroxyphthalic acid, malic acid, and other low-molecular compounds.

Also included in this group are partially saponified vinyl acetate-acrylic acid copolymers, modified ethylene-propylene copolymers (modified with acrylic acid and sulfuroxyethylmethacrylic acid), and modified ethylene-zolopylene-dicyclopentadiene copolymers. (modified with acrylic acid and allyl alcohol), modified ethylene-acrylic acid copolymer (modified with ethylene glycol), modified ethylene-propylene copolymer (modified with maleic anhydride and allyl alcohol, It can be treated equivalently to two 2xyl groups.

) and other polymer compounds.

The second group of polyfunctional compounds are compounds containing three or more hydroxyl groups and three or more amino groups in one molecule.

This group includes low molecular weight compounds such as λ-amino-1,4-butanediol, jetanolamine, jetanolamine, and -monamino-1,4-cyi-roxybenzene.

This group also includes N-methylolated nylon 6 (
amine group terminal), N-methylolated, iron 6-6 (
There are polymer compounds such as partially saponified reduced vinyl acetate-acrylonitrile copolymer.

The third group of polyfunctional compounds are compounds containing three or more carboxylic groups and amino groups in one molecule.

This group includes low-molecular compounds such as -monoaminoadipic acid, 2-aminoterephthalic acid, and 3-aminoheptadalic acid.

Also included in this group are acrylic acid-p-aminostyrene copolymers and modified ethylene-methacrylic acid copolymers (
There are polymer compounds such as hexamethylenediamine-modified) and modified methyl methacrylate-methacrylic acid copolymer (tetramethylenediamine-modified).

The fourth group of polyfunctional compounds is a compound containing three or more hydroxyl groups, carboxylic groups, and amino groups in one molecule.

Cono/Loose has λ-amino-4-hydroxybenzoic acid, phosphorus! There are low molecular weight compounds such as acid monoamide and tartaric acid monoamide.

Also included in this group are partially saponified vinyl acetate-acrylic acid-acrylamide copolymer, N-methylolated nylon 6-6 (carboxyl group, amine group terminal), N-dimethylolated nylon 12 (carboxyl group, amine group terminal)
There are polymer compounds such as

When the molecular weight of the polyfunctional compound is low, chain branching is likely to occur. However, the impact properties of the acetal polymer produced are not significantly improved. On the other hand, when the molecular weight of the polyfunctional compound is high, chain branching is less likely to occur, but on the contrary, the impact properties of the acetal polymer are often greatly improved.

Therefore, it is necessary to strike a balance between improving fluidity resulting from chain branching and improving impact properties.

The polyfunctional compounds are subjected to the polymerization reaction alone or in combination. Furthermore, prior to the polymerization reaction, it is desirable to remove impurities such as water contained in the polyfunctional compound as much as possible.

In the present invention, catalysts generally known as anionic polymerization catalysts and coordination anionic polymerization catalysts can be used for formaldehyde polymerization. Representative groups of these catalysts include alkali metals such as sodium and potassium, alkali metal complexes such as sodium-naphthalene and potassium-anthracene, alkali metal hydrides such as sodium hydride, and alkaline earths such as calcium hydride. Metal hydrides, sodium methoxy r1 potassium t-
Alkali metal alkoxides such as butoxide and potassium octoxy P, alkali metal salts of carzenate such as sodium caproate and potassium stearate, alkaline earth metal salts of carzenate such as magnesium casilonate and calcium stearate, n-butylamine, dibutylamine 1 ．．
Amines such as distearylamine, trioctylamine, pyridine, ammonium sudearate, tetrazotylammonium methoxide, tetrabutylammonium octanoate, dimethyldistearylammonium acetate, trimethylpendylammonium acetate, trimethylbenzylammonium methoxide, etc. Quaternary ammonium salts of tetramethylphosphonium propionate, trimethylbenzylphosphonium ethoxide, tetrabutylphosphonium stearate and other phosphonium salts, tributyltin chloride P1, diethyltin dilaurate, dibutyltin dimethoxide, dibutyltin dilaurate, dioctyltin dilaurate and tributyltin laurate, alkyl metals such as n-butyllithium and ethylmagnesium bromide, and organic chelate compounds such as trisacetylacetonate.

Still in the present invention, the polymerization is usually carried out in an organic medium. Organic media that can be used in the present invention include n-
Aliphatic hydrocarbons such as hexane, n-hezotane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene 1. Examples include halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and trichloroethylene, halogenated aromatic hydrocarbons such as chlorobenzene, and ether compounds such as ethyl ether and tetrahyprofuran. These organic media may be used alone or in combination of two or more.

The formaldehyde used in the present invention needs to be substantially anhydrous and needs to be purified using a known method such as a cold trap method or a solvent washing method.

For the production of the acetal polymer of the present invention, conventionally known formaldehyde polymerization methods such as blow polymerization and solution polymerization can be used.

The blow polymerization method is a method in which formaldehye P gas is directly blown into an organic medium containing a polymerization catalyst and a polyfunctional compound, and the solution polymerization method is a method in which the organic medium containing a polyfunctional compound is cooled and the organic medium containing a polyfunctional compound is cooled. In this method, after formaldehye P is absorbed into a solution, a polymerization catalyst is added to start polymerization.

The polyfunctional compound is used after being uniformly dissolved or dispersed in an organic medium. The concentration of the polyfunctional compound in the organic medium can be easily determined experimentally depending on the molecular weight requirements of the desired acetal polymer.

The polymerization catalyst is IXIG-2 to IX 10-' mol/L
- used in concentrations of organic media.

The polymerization temperature is -50 to 118°C in the case of the blow polymerization method.
In the case of solution polymerization, the temperature is often set between -70 and 50°C.

There is no particular restriction on the polymerization time, but it is between 5 seconds and 30 seconds.
Set between 0 minutes.

After completion of the polymerization, the acetal polymer is separated from the organic medium, and then the terminal unstable portions are blocked by a known method, such as an esterification method, an etherification method, or a urethanization method. After stabilizers, antioxidants, etc. are added to the end-capped polymer, the polymer is put into practical use.

By using the manufacturing method of the present invention described in detail above,
It became possible to obtain an acetal polymer having a desired molecular weight and excellent fluidity and impact properties. Here, the features of the present invention are listed as follows.

(1) It is possible to arbitrarily control the molecular weight of the acetal polymer.

(2) It is possible to control the molecular weight and at the same time impart excellent fluidity and impact properties to the acetal polymer.

The present invention will be explained below with reference to Examples, but these are not intended to limit the scope of the present invention. The measurement items in the following examples are as follows.

MI, M, F, R,; After blocking the ends of the polymer with acetic anhydride, 2,2-methylene-bis(
4-methyl-6-tert-butylphenol) 0.2
5 parts, added 0.50 parts of nylon 6-6, 50 w
Mix using an extruder to form pellets.

The melting index (MI) of this pellet was set to 2 at 190°C.
．． Measured using a standard load of 16Kg (ASTM D
1238-57T). MI is a measure of the molecular weight of an acetal polymer. In addition, the melting index (toxMI) of this pellet under high load was 21.60Kg at 190tl.
Measure using a high load. Then, M, F according to the following formula
, R, (Melt Flow Ratio).

10XMI MI M, F, L is a measure of the fluidity of the acetal polymer, and the higher the M, F, R, is, the better the fluidity is.

Izot impact value (notched): After molding the above pellet into a flat plate using molding a, a test piece was cut from the flat plate and measured according to ASTM D 256.

The larger the Izot impact value, the better the impact S% property.

Example 1 Thoroughly dehydrated and dried ξla formaldehyde was added to 150
The mixture was thermally decomposed at a temperature of 0.degree. C. and passed through a cooling trap several times at t-at to obtain formaldehyde gas with a purity of 99.9%. 1
100 parts per hour (the following parts indicate parts by weight) of formaldehyde gas were used as an anionic polymerization catalyst, and 2.4
10-' mol/X dimethyl distearyl ammonium acetate, 7.9 wt as molecular weight regulator
% of modified ethylene-propylene copolymer into 500 parts of cyclohexane. The modified ethylene-propylene copolymer used in this practical example was prepared by adding methacrylic acid, 2-hydroxyethyl methacrylic acid, and dicumyl peroxide to the ethylene-propylene copolymer.
It was modified in a zero temperature extruder at 215° C. and has an MI of 5.3 (p/lo min).

Moreover, this polymer has an average of three hydroxyl groups and two carzexyl groups in one molecule.

At the same time as formaldehyde gas supply, 2.4X10-
Cyclohexane containing mol/A of dimethyldistearylammonium (1=7-) and 7.9% by weight of a modified ethylene-zoropyrene copolymer was continuously fed at a rate of 500 parts per hour for 3 hours. Formaldehyde gas was also continuously supplied for 3 hours at a rate of 100 parts per hour.
During this time, the polymerization temperature was maintained at 55°C. Cyclohexane containing the acetal polymer was continuously extracted in proportion to the amount supplied, and the diacetal polymer was separated by filtration. After thoroughly washing the acetal polymer with hot xylene, heat at 60°C.
The mixture was dried under vacuum to obtain 355 parts of a white polymer. The physical properties of this acetal polymer are as follows.

Ml 12.5 (y710 min) M, F', R
,26,6 Izot impact value 18.8 (K9・m/crn
) The acetal polymer obtained in this example has a desired molecular weight and is also excellent in fluidity and impact properties.

Examples 2 to 13 Formaldehyde gas with a purity of 99.9% per hour,
! 7100 parts of dibutyltin dimethoxy r1 as an anionic polymerization catalyst was continuously fed into 500 parts of hexane containing the compound shown in Table 1 as a molecular weight regulator for 5 hours. Hexane containing dibutyltin dimethoxy P and the molecular weight regulator shown in Table 1 was also fed at a rate of SOO parts/hr for 5 hours, and the polymerization temperature was maintained at 52°C. A diacetal polymer was obtained by separating the polymer with hexane and then washing and drying. The physical properties of the obtained acetal polymer are also shown in Table 1. In all Examples, acetal polymers having the desired molecular weight and excellent fluidity and impact properties were obtained.

Comparative Example 1 Among the reagents used in Example 1, Cal? The same reagents and operations as in Example 1 were used except that adipic acid having two xyl groups in one molecule was used as a molecular weight regulator. The results are shown in Table 1. Although it is possible to control the molecular weight by using adipic acid, the fluidity and impact properties of the resulting polymer are poor.

Comparative Example 2 Among the reagents used in Example 1, in place of the modified ethylene-zolopyrene copolymer, zolopionic acid having one carxyl group in one molecule was used as a molecular weight regulator.
All the same reagents and operations as in Example 1 were used. The results are shown in Table 1. Although it is possible to control the molecular weight by using propionic acid, the resulting polymer has poor fluidity and poor impactability.

Comparative Example 3 Among the reagents used in Example 1, glycolic acid having one hydroxyl group and one carboxyl group was used as a molecular song modifier instead of the modified ethylene-zoropyrene copolymer. All the same reagents as in Example 1 were used and the procedure was the same as in Example 1. The results are shown in Table 1. Although it is possible to control the molecular weight by using glycolic acid, the fluidity and impact properties of the resulting polymer are poor.

(Remains below) Procedural amendment (voluntary) 1. Display of case ° 1982 Patent Application No. 104872
No. 2, Name of the invention Process for producing acetal polymer 3, Relationship with the case of the person making the amendment Patent applicant 4, Column 5 of "Detailed description of the invention" of the specification to be amended, Contents of the amendment (1), In Table 1, page 20 of the specification, the number of hydroxyl groups in the molecular weight regulator, tartaric acid, in column 3, "1", is corrected to "2".

that's all , -113-

Claims (1)

[Claims] L: Anionic polymerization of formaldehyde in the presence of a polyfunctional compound containing three or more functional groups of at least two types selected from the group consisting of a hydroxyl group, a carboxylic group, and an amino group. Characteristic method for producing an acetal polymer 2 The method for producing an acetal polymer according to claim 1, wherein the polyfunctional compound is a compound containing three or more hydroxyl groups and carboxyl groups in one molecule; Production method 4 according to claim 1, which is a compound containing three or more hydroxyl groups and amino groups in one molecule, wherein the polyfunctional compound contains three or more hydroxyl groups and amino groups in one molecule. A manufacturing method according to claim 1, which is a compound containing three or more groups in total; and a patent in which the polyfunctional compound is a compound containing three or more groups in total, including a hydroxyl group, a carboxyl group, and an amino group in one molecule. Manufacturing method according to claim 1