JPS62232474A - Milk white cyanoacrylate adhesive and coating agent - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to cyanoacrylate adhesives and coatings which exhibit opalescence after curing by incorporating selected semi-compatible plasticizers.

=6- Cyanoacrylates are generally transparent, high shear strength adhesives that can form instant bonds to a wide variety of surfaces. This transparent material produces a bond line with a non-obtrusive decorative appearance and is therefore very convenient for most applications. However, in some cases a material is required that produces an opalescent bond line. This requires relatively high visibility of the bond line for inspection purposes. Additionally, the colored opalescent cyanoacrylates provide improved decorative appearance or easier identification on certain substrates.

Cyanoacrylates can also form transparent, viscous plastic coatings. This coating can be used to provide gloss, scratch resistance, chemical resistance, electrical resistance and improved structural performance. When dry, this material has a color coded surface that is difficult to mark.
lorcoding). However, on black or dark-colored surfaces such coatings have poor visibility due to their transparency. For example, if black rubber is coated with a conventionally colored cyanoacrylate, it is extremely difficult to determine the colors used to color the rubber.

The opalescent cyanoacrylate is visible in the coating due to its whitening effect, making the color of the dye clearly visible on the black surface.

To make most ingredients opalescent, white pigments, such as titanium dioxide or calcium carbonate, are added. However, such materials are strong activators for cyanoacrylates, resulting in adhesives with unfavorable shelf lives.

Plasticizers have been used in cyanoacrylate agents for a long time. For example, U.S. patent issued November 21, T.
H, Wicker: Specification No. 8,961,966, published June 8, 1976, B, Brinkmann
Used to make ugly cyanoacrylates somewhat more flexible. To obtain maximum flexibility in the adhesive bond, a plasticizer that is highly compatible with the cyanoacrylate polymer is used.

The present invention comprises the step of adding to at least one monomeric 2-cyanoacrylate an effective amount of a semi-unicompatible plasticizer, the plasticizer having a boiling point of 98°C (200°F) or greater and a non-containing plasticizer. a solvent selected from the group consisting of hydrogen bonding solvents or moderately hydrogen bonding solvents, the solvent being soluble in the monomer 2-cyanoacrylate and insoluble in the polymerized 2-cyanoacrylate; The aim is to provide a method for converting The preferred amount of plasticizer is 20-30% by weight, generally using 5-50% by weight plasticizer per monomer ester. The mixture of semi-compatible plasticizer and liquid adhesive or coating is a clear solution. It turns opalescent when used as an adhesive. This is because the plasticizer becomes incompatible with the polymerization of the cyanoacrylate monomer.

In case 2-3, uncontrolled whitening occurs outside the cyanoacrylate bond line. This is chlorosis (ch
lorosis). Chlorosis is undesirable and numerous patents are directed to methods of avoiding or reducing such whitening. For example, JP-A-55-94979, July 18, 1980; JP-A-55-28118
Publication, February 19, 1980; Japanese Patent Application Publication No. 1520-1983
Publication No. 88, November 29, 1979; JP-A-58-1
Publication No. 06784, September 18, 1978;
-880041, August 3, 1978; JP-A-5
8-81588, July 19, 1978; JP-A-52-187440, November 16, 1977;
and Japanese Unexamined Patent Publication No. 52-68284, June 6, 1977
See day. In contrast to non-reproducible whitening caused by chlorosis, which is sensitive to temperature, humidity, air flow and substrate surfaces, the composition according to the invention provides a reproducible bond line when the adhesive cures regardless of the above conditions. Some whitening occurs.

Selection of a suitable plasticizer used according to the invention - 10= is the solubility parameter of the plasticizer, i.e. the boiling point of the solvent used as plasticizer - which for most adhesive applications is at least 93°C (200°F)
Must be based on -. The solubility parameter is a measure of the cohesive energy density of a molecule. Molecules with identical solubility parameters are fully compatible. To determine suitable solubility parameter ranges for useful opacifying plasticizers, typical compounds with known solubility parameters are applied.

The solubility parameters of most low-boiling solvents are readily determined by quantifying their latent heat of vaporization.

If these solvents are listed in order of increasing solubility parameters, a solvent spectrum is obtained.

Generally this spectrum is divided into eight distinct ranges, namely 1
One is a non-hydrogen-bonding solvent, the other is a moderately hydrogen-bonding solvent, and the other is a strongly hydrogen-bonding solvent. The following table shows how these solvents are classified.

Hydrocarbon ethers Alcohols Hydrogenated hydrocarbons Ketones Carboxylic acid nitrohydrocarbons Esters Amines Water Strongly hydrogen-bonding solvents have an adverse effect on the storage stability and properties of cyanoacrylates, hence their use as opacifying agents. is inappropriate. For non-hydrogen bonding solvents, the solubility parameter must be greater than or equal to 7.4 and less than or equal to 11.1, generally between 7.8 and 8.7 for the use of ethyl cyanoacrylate and 8 for the use of methyl cyanoacrylate. Must be between .2 and 10.6. Suitable low-boiling solvents include methylcyclohexane 7 (7,8) and cyclohexane (7,8) for ethylcyanoacrylate.
8,2) and p-ethyltoluene ('8.7). For moderately hydrogen-bonding solvents, the solubility parameters are less than 7.4 to 9.6, typically 7.4 to 8.4 for the use of ethyl cyanacrylate and 7.4 to 8.4 for the use of methyl cyanacrylate. Must be 9.1. Suitable low-boiling solvents include diethyl ether (7,4) for ethyl cyanacrylate and n-butyl acetate' (8,5) and ethyl acetate (9,1) for methyl cyanacrylate. The low boiling solvents mentioned above provide opacification when the monomers are polymerized, but are insufficient for use at high temperatures. However, since compounds with the same solubility parameters have the same solubility characteristics, high-boiling plasticizers within the above-mentioned solubility parameter ranges provide opalescence and are sufficient for use at elevated temperatures. Suitable moderately hydrogen-bonding plasticizers with solubility parameters within the same range that are therefore useful for ethyl cyanacrylate include butyl stearate (7,5), diphthoxyethyl phthalate (S,O),
Tributyl phosphate (8,2), 2-ethylhexyldiphenyl phosphate (8,4) and dioctyl azelaate (
8,4). A suitable moderately hydrogen-bonding plasticizer with a solubility in the range suitable for methyl cyanoacrylate is butyl stearate (7,5).
, dibutoxyethyl phthalate (8,0),! Tributyl J phosphate (8,2), 2-ethylhexyldiphenyl IJ phosphate (8,4) and dioctyl hyazelaate (8,4)
, dioctyl phthalate (8,7), sonohodi9-tylphenyl (8,7), dioctyl adipate (8,7)
, dihexyl phthalate (8,9), tricresyl phosphate (9,0), dibutyl sebacate (9,2) and triphenyl phosphate (9,2). The solubility parameters of the above plasticizers are reported in 1 Plasticizers Technolonhold Publishers, New York (1965).

A non-hydrogen bonding solvent with solubility parameters within the range suitable for both ethyl and methyl cyanoacrylates are partially hydrogenated terphenyl compounds (8,7). It is available from Monsanto Company as HB-40■.

The α-cyanoacrylate monomers used according to the invention have the following formula: CH2=C-C-OR in which R is an alkyl group which may be substituted by a substituent, for example a halogen atom or an alkoxy group.
, represents an alkenyl group, an alkynyl group, a cycloalkyl group, an aralkyl group, or an aryl residue. ) is a compound. Examples of particularly suitable R groups include methyl-, ethyl-1n-propyl-, isopropyl-1n-
Butyl, inbutyl, benzyl, hexyl, benzyl, octyl-1n-decyl, undecyl,
Dodecyl, cetyl, vinyl, allyl, metaolyl, crotyl, propargyl, cyclohexyl
, benzyl-phenyl-, cresyl-, trifluoroethyl-12-methoxyethyl-12-methoxyisopropyl-12-ethoxyf-, 2-10-ethyl-,
2-fluoroethyl-, hexafluoroisobutyl-, and 2'-jcya, -ethyl groups, and the like.

Preferred cyanoacrylates are methyl and ethyl cyanoacrylates. Monomer esters of 2-cyanoacrylic acid can be prepared by known methods, e.g., U.S. Pat. No. 2,467.
．． 927, 1949.

The adhesive or coating composition according to the invention may contain various additives,
For example, they may contain stabilizers, thixotropic agents, crosslinking agents and colorants.

Suitable stabilizers are antioxidants or radical polymerization inhibitors, such as sulfur dioxide, sulfonic acids, boron 1. Includes fluoride, hydroquinone, hydroquinone monomethyl ether, catechol and pyrogallol. These can be added in varying amounts; generally the amount is about 0.0001 to 5%, based on the cyanoacrylate. Suitable chiktropic agents include chemically treated caposils (ie, fumed silica).

Polymers that are miscible with cyanoacrylates, such as poly-(methyl methacrylate), poly-(α-cyanoacrylate) and acrylic rubber, can be used as thickeners.

The amount added can vary within a wide range.

Plasticizers such as dioctyl phthalate, sebacate or phosphate esters are not necessary in the present invention. This is because opacifiers also act as plasticizers. Additional plasticizers may be used, however, if required.

The crosslinking agent serves to improve the resistance of the bonded coating by converting the linear cyanoacrylate into a three-dimensional network. Suitable crosslinking agents are polyfunctional compounds, such as alkylene diacrylates, alkylene dimethacrylates,
These are trimethylolpropane triacrylate and triallyl isocyanate.

Although a colorant is not required in the present invention, it may be used to produce an opalescent colored adhesive. Usually oil-soluble dyes and colorants are used.

Other additives, which are normally within the scope of cyanoacrylate production technology, may be included in the compositions according to the invention without departing from that purpose, if this adversely affects the opacity.

Such additives can be produced.

In the following examples, all "parts" are "parts by weight" and all temperatures are "°C" unless otherwise specified.

The overlap shear strength was measured using ASTM method D1002-72 (197
Perform 4 tests according to 8). Applying 5 μl of adhesive between the clean surfaces of the substrates exhibiting a cure time of less than 5 seconds;
Test and measure until hand strength is observed.

Example 1 This example determines which non-hydrogen bonding solvents and moderately hydrogen bonding solvents are incompatible and which exhibit a range of solubility parameters for compatible plasticizers.

Ethyl cyanoacrylate and methyl cyanoacrylate-1 adhesives that have not become sticky are diluted with 30% of the indicated solvent, and the customer level is examined. The opacity of the compatible adhesive-solvent mixture was then determined by applying a drop of this mixture onto a piece of black rubber treated with a commercially available cyanoacrylate accelerator (sold as Permabond QFS by National Starch and Chemicals). Apply it to the surface and measure it.

After 1 hour, the material is visually inspected and considered opalescent if the cured adhesive is significantly whiter than the solvent-free cured cyanoacrylate. The results are shown in Tables 1 and 2.

The results show that the following solubility parameter criteria are obtained corresponding to the material acting as an opacifier.

When a non-hydrogen bonding solvent is used as an opacifying agent,
7.4 and 8.9, preferably 7.8 to 8.7, when a moderately hydrogen bonding solvent is used as an opacifying agent, (8
,5, preferably about 7.4 to 8.4.

When a non-hydrogen bonding solvent is used as an opacifying agent,
7.8 and (11,1, preferably 7.8-8.7, when a moderately hydrogen-bonding solvent is used as an opacifying agent,
9.6, preferably between 7.4 and 9.1.

EXAMPLE ■ This example shows that high boiling point solvents within the indicated solubility parameters yield opalescent hardened adhesives with satisfactory adhesive properties. The stabilized adhesive composition contains 80% detackified ethyl cyanoacrylate and 20% partially hydrogenated terphenyl compound having a solubility parameter of 8.7 (determined by the method described above). The solvent, available as HB-400 from Monsanto, is a high boiling aromatic compound (180°C at 10mmHg);
This compound solvates various polymers, rubbers, asphalts and tars. It is a clear oily liquid that is virtually insoluble in water and has a density of approximately 8.41 bs/ga1. (25℃
), have a pour point of -26°C and a viscosity of 70.29 and 8.8 cps at 0°, 87.8° and 98.9°C, respectively.

Both new and old adhesive compositions are evaluated. The results are shown in Tables ■, ■, and V.

Table - New Adhesive Milky Ethyl Clear Ethyl Cyanoacrylate Cyanoacrylate (Control) Viscosity 8.68
8.882 minute steel shear (psi) 7
53 164015 minutes //
687 1”16724 hours I
I, 2458 246
02 hours Rubber Shear (psi) 45
22424 hours Plastic shear (psi
) Acrylonitrile-butadiene-styrene 920 tatami +
988+ Tatami polystyrene
63B4 653 phenol 727 1100 tatami holica pollinate 1460 tatami
953 Zytel Nye 07
821 152*+Curing time Steel (sec) 15-2010 Phenolic resin (sec) 10-15
5 Buna-N rubber (sec) 0-57 41 tatami indicates base damage.

No.1 Adhesive left at -70℃ for 5 days Milky white ethyl transparent ethyl cyanoacrylate Cyanoacrylate (control viscosity (cps, ) 6.09
4.792 steel shear (psi)
487 176715 minutes //
1067 165824 hours tt
2140 2158 Milky-white ethyl Transparent ethyl cyanoacrylate] Cyanoacrylate Yuushi Shojiko L- Acrylonitrile-butadiene-styrene (psi) 920++
983+41 polystyrene (psi)
560ro 5380 phenol (psi)
287 860+*Polycarbonate (psi) 1040 tatami
1013 tatami bone water nylon (psi)
44 40 tatami mats indicate damage to the base.

The results show that Opalescent Cyanoacrylate Adhesive achieves the same strength on steel and most plastics, albeit somewhat lower than HaControl Cyanoacrylate adhesive. Relatively low strengths are observed for both rubber and phenolic resins. Opalescent adhesives also exhibit good, uniform aging properties.

Example ■ This example compares to the non-tackified adhesive of Example ■ even using tackified and stabilized ethyl cyanoacrylate (80% ethyl cyanoacrylate and HB-4020 with a viscosity of about 2000 cps). showing that there is little relative change in adhesive properties. The results are shown in Table ■.

Table ■ Viscosity (cps) 1620
20902 steel shear (psi) 50
7 188015 minutes tt
7'18 165024 hours tt
1973 22252 hours Rubber (psi) 168
501 tatami mat curing time (seconds) Steel 20
20 Phenol resin 15
15 Buna N-Rubber 23
The 20 tatami area shows damage to the base.

Example 1 shows the use of a high boiling solvent with methyl cyanoacrylate as an opacifying agent.

The adhesive composition is 80% detackified methyl cyanoacrylate and 20% triethylene glycol di-2-ethylhexanoate (CAS Reg.

No, 94-28-0)-This is Ey,, l--
Contains 27-dafflex available from 7 companies. The solubility parameter of the solvent is 8.5.

This is 344°C and 219°C at 760 and 5 mmHg.
Boiling point of 15.8 CP at 20°C Viscosity of 20/20°C
has a specific gravity of 0.967. The results are shown in Table ■.

Table ■ Viscosity (cps,) 8.71
8.522 minute steel overlap shear (psi) 1
00 82015 minutes tt
418 156024 hours 1/
1640 21402 hours Rubber (psi) 27 104
Hardening time (seconds) Steel 85-40 20-
25 Phenol resin 5-105-10
Buna-N5-10 seconds 5-10 seconds The results show that the opalescent adhesive has some loss in final strength on steel, the strength increase on steel occurs gradually, and the rubber adhesion decreases. It is nevertheless suitable for applications requiring the use of opalescent methylcyanoacrylate.

Example V This example is applied to a colored opalescent cyanoacrylate tackified and stabilized ethyl cyanoacrylate adhesive. The material turns milky red as it hardens.

Its adhesive properties are as follows: 2 minutes steel overlap shear (psi) 7
2515 minutes 〃730 24 hours 1/2
4162 hours Rubber (psi)
62 Results indicate that this agent has reduced adhesive properties or is useful in a variety of temporary adhesive applications.

EXAMPLE ■ The colored opalescent cyanoacrylate agent of Example ■ is coated onto a piece of Black Buna-N rubber whose surface has been washed with acetone. After 24 hours, the rubber has a bright red coating.

This is clearly visible under uniform dim illumination conditions.

A comparative colored cyanoacrylate agent is prepared in a similar manner. However, a completely compatible plasticizer (ie, dibutyl phthalate) is used in place of the semi-compatible plasticizer HB-40. This control agent is coated onto a piece of Black Buna-N in the manner described above.

A non-opalescent coating develops, the color of which is almost indistinguishable.

Only cyanoacrylate agents containing semi-unicompatible plasticizers are suitable for colorcoding this material.

Example ■ A black ferrite core is soaked in the colored cyanoacrylate agent of Example ■ containing HB-40.

The coated core is then soaked in a commercially available cyanoacrylate promoter (ie, a solution containing the amine in a carrier solvent). The coating cures in about 1 hour of processing. A milky white color begins to appear after about 5 minutes and changes over 6 to 24 hours with full color development. The end result is a 1/8' thick coating with a highly visible red color. When the same procedure is carried out using the colored control agent of Example 1 (ie, the agent containing dibutyl phthalate), it forms a non-opalescent coating with only a slight discernible color.

Only cyanoacrylate agents with semi-unicompatible plasticizers are suitable for coloring this material.

Claims (1)

Claims: 1) adding to at least one monomeric 2-cyanoacrylate an effective amount of a semi-compatible plasticizer, the plasticizer having a boiling point of 93°C (200°F) or greater; and is selected from the group consisting of non-hydrogen-bonding solvents or moderately hydrogen-bonding solvents, the solvent being soluble in the monomer 2-cyanoacrylate and insoluble in the polymerized 2-cyanoacrylate. Method for opacifying acrylate compositions. 2) The monomeric cyanoacrylate is ethyl cyanoacrylate and the solvent is a non-hydrogen bonding solvent with a solubility parameter of 7.4 or more and 8.9 or less or 7.4 to 8
．． The monomeric cyanoacrylate is methyl cyanoacrylate and the solvent is a moderately hydrogen bonding solvent with a solubility of less than 7.8 and 11.
Claim 1 which is a non-hydrogen-bonding solvent with a solubility parameter of 1 or less or a moderately hydrogen-bonding solvent with a solubility parameter of 7.4 to less than 9.6.
The method described in section. 3) The monomeric cyanoacrylate is ethyl cyanoacrylate, the non-hydrogen-bonding solvent has a solubility parameter of 7.8-8.7, and the moderately hydrogen-bonding solvent has a solubility parameter of 7.8-8.7.
4 to 8.4, or the monomeric cyanoacrylate is methyl cyanoacrylate and the non-hydrogen bonding solvent is a partially hydrogenated terphenyl compound having a solubility parameter of about 8.7. The method described in Scope No. 2. 4) The monomeric cyanoacrylate is ethyl cyanoacrylate, the non-hydrogen-bonding solvent is a partially hydrogenated terphenyl compound with a solubility parameter of 8.7, and the moderately hydrogen-bonding solvent is butyl stearate, phthalate or the monomeric cyanoacrylate is methylcyanoacrylate selected from the group consisting of dibutoxyethyl, tributyl phosphate, 2-ethylhexyldiphenyl phosphate and dioctyl azelate;
Solvents that form moderate hydrogen bonds include butyl stearate, dibutoxyethyl phthalate, tributyl phosphate, 2-ethylhexyldiphenyl phosphate, dioctyl azelaate, dioctyl phthalate, dibutylphenyl phosphate, dibutyl adipate, dihexyl phthalate, phosphorus. 4. The method of claim 3, wherein the selected member is tricresyl acid, dibutyl sebacate, and triphenyl phosphate. 5) The monomeric cyanoacrylate is ethyl cyanoacrylate and the moderately hydrogen bonding solvent is triethylene glycol di-
2-ethylhexanoate, the monomeric cyanoacrylate is methyl cyanoacrylate, and the partially hydrogenated terphenyl compound is about 18
A method according to claim 3 having a boiling point of 0°C. 6) consisting of at least one monomeric 2-cyanoacrylate and an opacifyingly effective amount of a semi-compatible plasticizer;
The plasticizer has a boiling point of 93°C (200°F) or higher and is selected from the group consisting of non-hydrogen bonding solvents or moderately hydrogen bonding solvents, and the solvent is A cyanoacrylate composition that is soluble in acrylate and insoluble in polymerized 2-cyanoacrylate, thereby rendering the polymerized cyanoacrylate opalescent. 7) The monomer cyanoacrylate has the formula ▲ numerical formula, chemical formula, table, etc.
-12 alkyl group, C2-12 alkenyl group, C2-12 alkynyl group, aralkyl group or aryl residue. 7. A composition according to claim 6, wherein the plasticizer is present in an amount of 5 to 50% by weight based on the weight of the monomer 2-cyanoacrylate. 8) A composition according to claim 7, wherein the monomeric cyanoacrylate is ethyl cyanoacrylate or methyl cyanoacrylate and the plasticizer is present in an amount of 20-30%. 9) consisting of at least one monomeric 2-cyanoacrylate and an opacifyingly effective amount of a semi-compatible plasticizer;
The plasticizer has a boiling point of 93°C (200°F) or higher and is selected from the group consisting of non-hydrogen bonding solvents or moderately hydrogen bonding solvents, and the solvent is at least one bonded together by an in-situ polymerized layer of a cyanoacrylate composition that is soluble in the acrylate and insoluble in the polymerized 2-cyanoacrylate, thereby opacifying the polymerized cyanoacrylate. Multilayer consisting of two non-porous substrates. 10) at least one monomer 2-cyanoacrylate and an opacifyingly effective amount of a semi-compatible plasticizer, the plasticizer having a boiling point of 93°C (200°F) or greater, and non-hydrogen; A solvent selected from the group consisting of a bonding solvent or a moderately hydrogen bonding solvent, which solvent is soluble in the monomer 2-cyanoacrylate and insoluble in the polymerized 2-cyanoacrylate, whereby the polymerized cyanoacrylate A coating consisting of a non-porous substrate coated with an in-situ polymerized layer of a cyanoacrylate composition which opacifies the composition.