JP2680594B2 - Block copolymer dispersant - Google Patents

Description

BACKGROUND OF THE INVENTION Polymeric materials that are effective for dispersing pigments in organic solvents have long been known. The polymeric dispersants are typically of the AB or BAB type, in which a polar group known as the A segment is present in the molecule to facilitate attachment to the pigment surface and to serve as the B segment. The presence of at least one known non-polar moiety enhances the steric stabilization of the pigment particles in the dispersion.

Baker et al., In U.S. Pat. No. 3,912,677, disclose the advantages of polymers containing ionic groups in the specific case where the ionic groups are in the form of salts with salt-forming components or counterions. The salt-forming component has an affinity for the surface of the organic pigment particles and can react with the polar bond type ionic group so as to form a salt. However, it does improve the performance of the polymeric dispersant and does not require the use of special salt-forming components, the use of which may complicate the manufacture of the dispersant and introduce undesirable colors. Continuous efforts have been directed towards finding suitable dispersants.

(Summary of the Invention)

The present invention comprises block copolymers composed of similar monomers but exhibiting substantially different polarities (one of the blocks having a cationic ammonium, phosphonium, or sulfonium moiety) It is based on the discovery that it provides excellent performance as a pigment dispersant without the need for a complex salt forming component.

In particular, the invention provides a block copolymer consisting essentially of:

(A) has about 200 to 10,000 number average molecular weight of, and having the general formula CH ₂ = CHCO ₂ R and _{CH 2 = CCH 3 CO 2 R} ( wherein R is-20 alkyl or alkyl ether of carbon atoms At least one block prepared from at least one monomer selected from compounds of formula (A) is a compound of the general formula -A (R ⁴ ) _m X (where A is N, P , And S; R ⁴ is independently selected from alkyl or alkyl ethers of 1 to 20 carbon atoms, phenyl or substituted phenyl, and when A is N or P, m is 3,
When A is S, m is 2, and X contains at least two pendant ionic moieties (selected from halides and conjugate bases of organic acids) and the backbone of the block is ethylenic saturated unit] (about 0.1 to 50% by weight), and (b) has about 500 to 100,000 number-average molecular weight of, and having the general formula CH ₂ = CHCO ₂ R and _{CH 2 = CCH 3 CO 2 R} ( Wherein R is an alkyl or alkyl ether of 1 to 20 carbon atoms) and at least 1 prepared from a monomer selected from
Seed block (approximately 99.9-50% by weight).

The block copolymer is represented by the following structural formula.

(A) Formula [However, R ¹ = H or CH _3- , R ² = C _1-20 alkyl group or alkyl ether group, R ³ = -R ² -A (R ⁴ ) _m -X (where A is N, P or S, R ⁴ = C _1-20 alkyl group or alkyl ether group, phenyl group or substituted phenyl group, m is 3 when A is N or P, and 2 when A is S, and X is a halide Or a residue of a conjugate base of an organic acid), n ¹ and l represent the number of repeating units, l is a number of 2 or more, n ¹ is an integer of 1 or more, and the number of n ¹ + l is a number. And a block represented by the formula (b). (Wherein R ¹ and R ² are as defined above, n ² represents the number of repeating units, and represents a number sufficient to give a number average molecular weight of 500 to 100,000). (A) / (b) is a weight ratio of 0.1-50 / 99.9-
AB or BAB type block copolymers that are 50.

These compounds can be, and are preferably, produced by a group transfer polymerization technique, exhibit excellent performance as dispersants, and require a salt-forming counterion for sufficient performance. Absent.

[Detailed description of the invention]

Monomers that can be used in making the dispersants of the present invention include the acrylates and methacrylates (3-methacrylic acid acrylate) described in Webster, US Pat. No. 4,508,880, columns 8, lines 4-58. -Oxypropyl; and acrylic acid and 2-methacryloxyethyl linalate). Suitable monomers for the first block of the copolymer containing pendant ionic groups include dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate. Second copolymer
Suitable monomers in the case of block (b) are methyl methacrylate, butyl methacrylate and methacrylic acid 2
-Including ethylhexyl.

The polymers of the present invention can be prepared by conventional anionic polymerization techniques, whereby the first block of the copolymer is formed and, upon completion of the first block, the flow of the second monomer is reduced. Upon initiation, the next block of polymer is formed. However, the reaction temperature using the above techniques should be kept at a low level, e.g. 0-40C, so that side reactions are minimized and the desired block of the specified molecular weight is obtained. is there.

In order to obtain the desired molecular weight of each block, as well as the homogeneity in the block, the aforementioned Webster, US Pat.
Group Transfer Pol, as described in 8,880 (incorporated herein by reference).
ymerization) technology is advantageously and preferably used. The process allows the polymerization to be carried out, contrary to the random mode typical of polymer reactions, so that a substantially linear polymer having polymer chains of uniform and desired molecular weight can be produced. The monounsaturated monomer is contacted with an initiator and a catalyst system containing silicon, tin or germanium under conditions which proceed in a controlled manner.

In producing the dispersants of the present invention, the order in which the blocks are produced is not critical. Blocks containing pendant ionic moieties or blocks not containing these moieties can first be prepared.

A catalyst that can be used is U.S. Pat. No. 4,508,880.
No. column 11, lines 42-68, and 19
Includes those described in the same assignee's patent application filed March 1, 1985, filed by Deitzker et al., US Application No. 707,190, incorporated herein by reference.

Initiators that can be used include those shown in the Webster patent column 9, line 25 to column 10, line 13 above. A suitable initiator is 1- (2-trimethyl-
Siloxyethoxy) -1-trimethylsiloxy-2-methylpropene; 1- (2- [1-ethoxyethoxy] -ethoxy) -1-trimethylsiloxy-2-methylpropane; and 1-methoxy-1-trimethylsiloxy-2.
-Including methylpropene.

If the dispersant is prepared by first forming blocks without pendant ionic groups, then the same general procedure is used to react these blocks with blocks containing pendant ionic groups. To form. The same generality for these second blocks, except that the monomers and their relative amounts are chosen to have an average of at least two cationic units, or their precursors, in each block. Reactive agents are used. The cationic unit can be in the required quaternary or tertiary arrangement when polymerized, or is more typically and preferably a primary, secondary or tertiary amine, phosphine or thioether compound. They can be converted to the quaternary or tertiary state after forming the basic polymer structure. Although a wide variety of monomers can be used, for example, 2- (dimethylamino) methacrylate
Ethyl, 2- (diethylamino) ethyl methacrylate,
Methacrylates, including glycidyl methacrylate, as well as t-butylaminoethyl methacrylate, have been found to be particularly satisfactory. Similar monomers can be used to introduce phosphorus and sulfur based ionic groups, as will be apparent to those skilled in the art.

Pendant ionic moieties have the general formula -A (R ⁴⁾ _m X (wherein A is, N, is selected P, and from S, R ⁴ is from 1 to 20
Selected from alkyl or alkyl ethers of carbon atoms, phenyl or substituted phenyl, m is 3 when A is N or P, m is 2 when A is S, X is a halide or Selected from the conjugate bases of organic acids). Suitably, A is nitrogen and X is
It is selected from the group consisting of carboxylates, sulfonates and phosphates.

Following the formation of the basic polymer structure, the cationic precursor can be contacted with a conventional alkylating agent such as an alkyl halide, an alkyl sulfonate, an alkyl toluene sulfonate, a trialkyl phosphate or an aralkyl halide. Alkylating agents which have been found to be particularly satisfactory are methyl toluenesulfonate, dimethylsulfonate and benzyl chloride.

The physical properties of the block copolymers of the present invention, including the molecular weight of the block and the presence of ionic moieties in one of the blocks, can be determined by differential scanning calorimetry (DSC), nuclear magnetic resonance, gas chromatography and infrared analysis. Can be confirmed by conventional analytical techniques including. For example, the chemical composition of the block can be determined by ¹ H nuclear magnetic resonance ( ¹ H NMR) or infrared analysis, or by thermal decomposition or gas chromatographic analysis. The size of the block in the copolymer can be determined by micelle formation as measured by nuclear magnetic resonance, glass transition temperature, solubility or pseudoelastic light scattering.

The resulting block copolymer exhibits excellent performance as a dispersant. Therefore, they can be effectively used as pigment dispersants in the formation of paints and as oil additives. Pigment dispersions typically consist of pigments, solvents and dispersants, and are described, for example, in Baker et al., U.S. Pat.
It can be prepared as described in 2,677 (incorporated herein by reference). Although similar compounds have been used in the past in the past, the copolymers of the present invention were found to be ionic rosin acid or sulphonic acid type aromas which were previously found to be necessary for satisfactory dispersant performance. It is effective without the use of counterions such as group hydrocarbons. Moreover, the uniform block properties in the compounds of the invention are:
Provide improved and more reliable dispersant performance.

In the following examples, the quality of the dispersant is sand grinded with a mixture of pigment, solvent and dispersant, with a proportion of the dispersant producing a uniform dispersion, similar to stained glass at 250x optical magnification. It is measured by determining what looks like. Aggregated pigments, on the other hand, have colored islands interspersed with areas of the solvent that are relatively clear. The degree of dispersion is evaluated on any scale of 1 to 4 as follows: 1-A non-aggregated dispersion in which the pigment particles are uniformly separated and in which Brownian motion is evident.

2-Slightly aggregated dispersion in which the pigment particles are separated but immobile (no significant evidence of Brownian motion).

3-Aggregated dispersion in which pigment particles are loosely aggregated, with some voids between the aggregates.

4- A highly aggregated dispersion in which pigment particles are highly aggregated and have large voids between the aggregates.

The dispersants prepared in the examples were evaluated in solvents using various standard pigments. The solvents used were methyl isobutyl ketone (MIBK or M), toluene (T), xylene (X), and acetone (A). The following standard pigments were used in the evaluation: W505-Phthalocyanine Blue, Red Tone (Monastral Blue) W552-Phthalocyanine Blue, Aggregation Resistant Green Shade, Toner W573-Tetrachloro CPC Blue; Phthalocyanine Blue Toner, Green Shade, Improved rhe
ology) W673-Tetrachloroisoindolinone-Irgazin Yellow W805-Monastral Magenta-Quinacridone Type Magenta Toner W811-Monastral Red-Quinacridone Red Toner W853-Organic Red Tone-Quinacridone-Monastral Transparent Red B RT-233 In all the examples of the present invention, the block of the copolymer containing pendant ionic groups is about 200-10,000.
Blocks having a molecular weight of .about.100 and no pendant ionic groups had a molecular weight of 500-100,000. The particular molecular weight can be determined by one skilled in the art from the data presented in the particular examples. In all embodiments of the invention,
On average, at least two pendant ionic groups were present in each block (a) of the copolymer produced.

Example 1 316 g of tetrahydrofuran (THF), 0.5 mL in a reaction vessel
Xylene, 4.1 g of 1-methoxy-1-trimethylsiloxy-2-methylpropene (“initiator”), and 0.10
0 mL of 1 M tetrabutylammonium 3-chlorobenzoate in acetonitrile (“catalyst”) was charged. In order to produce an A block without pendant ionic groups,
Two feeds started simultaneously; methyl methacrylate (MM
A) 91.2 g was added in 20 minutes and 0.350 mL catalyst in 3 ml THF was added over 2 hours. Twenty minutes after the addition of MMA, 2-N, N-dimethylaminoethyl methacrylate (DME) was prepared in order to produce a block containing pendant ionic groups.
28.9 g of AMA) was added over 10 minutes. Twenty minutes after the addition of DMAEMA, 91.9 g of MMA was added over 20 minutes. One hour after the second addition of MMA, 5 ml of methanol was added.
This resin (251 g) was added to heptane (700 mL), the resulting solid was separated from the liquid, and this solid was added to 700 mL of heptane.
Washed with and dried.

In order to quaternize the amino groups in the obtained copolymer, a part (30.69 g) of the copolymer was dissolved in THF (50.5 g) and benzyl chloride (3.0 g) was added. The resulting solution was refluxed for about 3 hours and then 50.5 g of isopropanol was added.
Reflux was continued for another 5 hours. The resulting resin exhibited 22% solids and 0.31 mM / gram of tertiary amine content, indicating that the amino groups were substantially completely quaternized.

This copolymer was evaluated as a pigment dispersant, and standard pigment W5
05, W552, W573, W673, W805, and W811 MIBK (M
In I), a dispersion point of 1 was shown. This copolymer is MIBK,
It was also evaluated by the standard pigment W853 in acetone and toluene, giving points of M3, A1 and T3, respectively.

Examples 2-4 and Comparative Example A In Comparative Example A, an ABA block copolymer having a tertiary pendant ionic group linked to the B segment was prepared. The general composition of this block copolymer is 20/20 // 8 //
MMA / BMA // DMAEMA // MMA / BMA at expected polymerization degree of 20/20
Met. In Examples 2-4, this block copolymer was quaternized with three different quaternizing agents to form one composition of the invention.

In Comparative Example A, 1361 g THF, 21.5 g in the reaction vessel
Of initiator and 1.2 mL of catalyst were charged. 581.5 g of 41.3 wt% MMA in butyl methacrylate was added over 20 minutes while maintaining the reaction temperature between 20 ° and 35 ° C. using an ice bath. At the same time, a 150 minute feed of 2.4 ml catalyst in 2.6 ml THF was started. 45 minutes after the first monomer is supplied,
An additional 20 minute feed of 173.3 g of 2-N, N-dimethylaminoethyl methacrylate was added. 40 minutes after the second monomer feed was over, an additional 20 minute feed of 41.3 wt% MMA 505.1 g in BMA was added. Ice cooling was used again. After about 16 hours, methanol
40 ml was added.

The resulting block copolymer with tertiary pendant ionic groups was evaluated as a pigment dispersant and the results are summarized in Table I.

In Example 2, the block copolymer 51 of Comparative Example A was used.
A reaction mixture of 3.2 g, 126 g ethanol, and 25.0 g iodomethane was refluxed for 3 hours. The resulting block copolymers with quaternized pendant ionic groups were evaluated as pigment dispersants and the results are summarized in Table I.

In Example 3, the block copolymer 50 of Comparative Example A was used.
A reaction mixture of 0.2 g, 125 g ethanol, and 30.3 g benzyl bromide was refluxed for 16 hours. The resulting block copolymers with quaternized pendant ionic groups were evaluated as described above and the results are summarized in Table I.

In Example 4, the block copolymer 20 of Comparative Example A was used.
A reaction mixture of 0.2 g, 50.5 g isopropanol, and 11.5 g methyl p-toluenesulfonate was refluxed for 16 hours. The resulting block copolymers with quaternized pendant ionic groups were evaluated as described above and the results are summarized in Table I.

Example 5 An AB block copolymer having the general composition EHMA // DEAEMA 42 // 12 was prepared. 205 g of toluene in the reaction vessel, 1.94 g
Of initiator, as well as 0.111 mL of catalyst. At the same time, 5
Feed 0.222 mL of catalyst in mL of toluene for 1 hour, as well as 9
Feeding of 2.3 g of 2-ethylhexyl methacrylate for 20 minutes was started. After 40 minutes, 0.111 mL of catalyst was added. After a further 3 hours, 0.111 mL of catalyst was added and an additional 10 minute feed of 20.92 g of 2-N, N-dimethylaminoethyl methacrylate was added. After a further 16 hours, 5 mL of methanol was added.
A portion of the resulting resin (150g) was diluted with 37.61g ethanol, 9.16g benzyl bromide was added and the resulting mixture was refluxed for 18 hours.

This copolymer was evaluated as a dispersant for standard pigments and was found to give x4 points for pigment W505 and x1 points for pigments W573, W805, W811 and W853.

Examples 6-7 and Comparative Examples B-H In Examples 6-7 and Comparative Examples B-H, between block and random copolymers of similar composition, and quaternary of each pendant ionic moiety. The comparison was performed while changing the degree of chemical conversion.

When producing a random copolymer, 127.
2g toluene, 2.26g initiator, 74.5g BMA, 52.6g MM
A, 29.7 g of 2-N, N-diethylaminoethyl methacrylate, and 0.030 mL of catalyst were charged. The reaction temperature was kept below 40 ° C. while cooling. After 4 hours reaction, 5mL
Of methanol was added.

When producing a block-type copolymer,
0.3 g toluene, 0.5 ml xylene, 2.27 g initiator, 7
6.4 g BMA, as well as 54.0 g MMA, and 0.030 mL catalyst were charged. The reaction temperature was kept below 40 ° C. while cooling. After 70 minutes of reaction, co-feed of 29.4 g of DEAEMA over 10 minutes and 0.20 mL of catalyst in 5 mL of toluene over 20 minutes was started. After reacting for an additional 1 hour, 5 mL of methanol was added.

The resulting copolymers, which have tertiary pendant ionic groups and represent Comparative Examples B and C, were evaluated as dispersants for standard pigment W552, both showing A3, M4 and T4 points.

In Comparative Examples D-H and Examples 6 and 7, the block copolymers of Comparative Examples B and C were diluted by combining 65 g of resin and 19.5 g of isopropanol. A 20 g portion of the resulting resin was quaternized using 25 mol%, 50 mol%, 75 mol% or 95 mol% of methyl p-toluenesulfonate based on the amine content. The resulting solution is 10
It was kept at room temperature for a day. The resulting quaternized copolymer was evaluated as a pigment dispersant and the results are summarized below.

While the present invention has been described in detail, the present invention can be further summarized by the following embodiments.

(1) A block copolymer consisting essentially of (a) having a number average molecular weight of about 200 to 100,000 and having the general formula CH ₂ = CHCO ₂ R and CH ₂ = CCH ₃ CO ₂ R Wherein R is an alkyl or alkyl ether of 1 to 20 carbon atoms) and at least one block prepared from at least one monomer selected from compounds of the general formula -A (R ₁ ) _m X, where A is selected from N, P, and S; R ₁ is independently selected from alkyl or alkyl ethers of 1 to 20 carbon atoms, phenyl or substituted phenyl, A However, when N or P, m is 3,
When A is S, m is 2, and X contains at least two pendant ionic moieties (selected from halides and conjugate bases of organic acids) and the backbone of the block is ethylenic A saturated unit] (about 0.1 to 50% by weight), and (b) a number average molecular weight of about 500 to 100,000 and having the general formula CH ₂ ═CHCO ₂ R and CH ₂ ═CCH _3. At least one prepared from a monomer selected from compounds of CO ₂ R, wherein R is an alkyl or alkyl ether of 1 to 20 carbon atoms
Seed block copolymer (about 99.9-50% by weight).

(2) the copolymer is at least 2 of the type defined in (b)
The block copolymer according to (1) above of the BAB sequence containing the seed block.

(3) The above (1), wherein A is N in the pendant ionic group.
The block copolymer described in 1.

(4) The block copolymer as described in (3) above, wherein the conjugate base of the organic acid is selected from carboxylate, sulfonate and phosphate.

(5) The pendant ionic group of the block (a) is derived from dimethylaminoethyl methacrylate (1).
The block copolymer described in 1.

(6) The pendant ionic group of the block (a) is derived from diethylaminoethyl methacrylate (1) above.
The block copolymer described in 1.

(7) The block copolymer as described in (1) above, wherein the block (b) is polymerized from methyl methacrylate.

(8) The block copolymer as described in (1) above, wherein the block (b) is polymerized from butyl methacrylate.

(9) The block copolymer according to (1) above, wherein the block (b) is derived from 2-ethylhexyl methacrylate.

(10) The block copolymer as described in (1) above, wherein the block (b) is derived from butyl methacrylate and 2-ethylhexyl methacrylate.

(11) The above (1) produced by a group transfer polymerization technique
The block copolymer described in 1.

(12) A dispersion containing a pigment, an organic liquid, and the block copolymer described in (1) above.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area C08F 220: 10)

Claims (3)

(57) [Claims] (1) Expression (a) [However, R ¹ = H or CH _3- , R ² = C _1-20 alkyl group or alkyl ether group, R ³ = -R ² -A (R ⁴ ) _m -X (where A is N, P or S, R ⁴ = C _1-20 alkyl group or alkyl ether group, phenyl group or substituted phenyl group, m is 3 when A is N or P, and 2 when A is S, and X is a halide Or a residue of a conjugate base of an organic acid), n ¹ and l represent the number of repeating units, l is a number of 2 or more, n ¹ is an integer of 1 or more, and the number of n ¹ + l is a number. And a block represented by the formula (b). (Wherein R ¹ and R ² are as defined above, n ² represents the number of repeating units, and represents a number sufficient to give a number average molecular weight of 500 to 100,000). (A) / (b) is a weight ratio of 0.1-50 / 99.9-
AB or BAB type block copolymers that are 50. 2. The block copolymer according to claim 1, which is produced by a group transfer polymerization technique. 3. A dispersion containing a pigment, an organic liquid, and the block copolymer according to claim 1.