Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
  • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C09D133/062—Copolymers with monomers not covered by C09D133/06
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F246/00—Copolymers in which the nature of only the monomers in minority is defined
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/062—Copolymers with monomers not covered by C08L33/06

Definitions

• the invention relates to the field of aqueous crosslinking dispersions and in particular to the field of aqueous crosslinking dispersions at ambient temperature at the time of filming without the intervention of external agents.
• These dispersions are used in the coating industries, in particular in paints, adhesives, paper, leather, textiles and inks.
• the film-forming dispersions used in the industries described above contain particles of polymers as binders. This requires in most cases a post-crosslinking intended to improve the properties of the coatings obtained, in particular the resistance to solvents, the mechanical properties and the reduction of surface tack.
• the crosslinking step must be adapted to the conditions of implementation and the field of application.
• the crosslinkable systems at low or medium temperature are generally based on the combination of two elements which are the use of functional monomers copolymerized during the synthesis of the binder and the addition after the synthesis or at the time of implementation of a cross-linking multifunctional agent.
• EP 552469, EP 555774 and EP 653469 describe the crosslinking of a functional latex based on acetoacetoxyethyl with a polyamine.
• EP 581466 crosslinks the same latex with a polyaldehyde.
• the major drawback of these systems is that the crosslinking agent is generally a small molecule added to the solution after the synthesis of the latex. This molecule, by its size and its partition coefficient between aqueous phase and organic phase (polymer) diffuses in the polymer, causing pre-crosslinking and making storage of the dispersion difficult, even impossible.
• the problem which the invention seeks to solve is to find an aqueous dispersion which is stable on storage and which leads, at the time of filming at low temperature, to a crosslinked film without the intervention of crosslinking agents.
• the Applicant has found that aqueous dispersions based on functionalized acetal polymers or aldehydes synthesized in an acid medium constitute an ingenious solution to the problem mentioned above.
• crosslinking is carried out without the intervention of crosslinking agents, these systems are called, within the meaning of the invention, single-component systems.
• composition of the invention is that the active function of the crosslinking is the aldehyde function. This is latent in the latex due to the presence of water, in the form of the hydrated aldehyde function and can only be generated during the evaporation of water. It can then react with itself or with acrylamide to lead to crosslinking at room temperature.
• This aldehyde function can be obtained by copolymerization of an aldehyde monomer, of an acetal monomer in an acid medium or by acidification of a functionalized acetal latex synthesized in a neutral or basic medium.
• Another advantage lies in the fact that the absence of a small reactive molecule capable of diffusing into the particles guarantees better storage stability.
• One of the objects of the invention is an aqueous dispersion of particles of at least one polymer with a diameter of between 50 and 500 nm, said polymer consisting of: from 0.1 to 50% by weight of the residue of monomer A carrying a function acetal, aldehyde or masked acetal, of
• the monomers A are chosen from group I containing
• - aldehydes such as acrolein, methacrolein, formyl styrol, crotonaldehyde.
• R2 and R3 identical, each represent a C- alkyl group
• - Cs, or else together form a group - CH 2 -CR S R 6 - (CH 2 ) ⁇ - where n O or 1, R5 and Rg which are identical or different, each represent hydrogen or methyl,
• R4 represents a C2 - C4 alkylene
• - E represents O, NH or NR 'where R' represents a hydrogen or a C 3 -C 3 alkyl
• - G represents a C- alkylene residue
• R7 represents hydrogen or C-] - C4 alkyl.
• the preferred monomer A1 can be chosen from: - N- (2,2-dialkoxy 1-hydroxy ethyl) - (meth) acrylamides and
• N- (1,2,2-trialkoxy ethyl) - (meth) acrylamides the term alkoxy meaning C1-C4 alkoxy, such as
• MAAMA diethyl acetal
• A1 is DMH or MAAMA. 5
• the monomer B is chosen from group II containing:
• R 9 H or C Problem 2 F 2n 2 + l
• acetal functionalized latexes can be obtained in accordance with the emulsion polymerization techniques known to a person skilled in the art by copolymerization of an acetal monomer (DMH,
• the acetal functionality can also be obtained by synthesis of a functionalized acrylamide latex or by synthesis of a latex comprising an acrylic monomer, then a posteriori modification of the latex respectively, by dimethoxy ethanal (DME) according to US 491 81 39, or by transesterification in the presence of a titanate type catalyst with the amino butyraldehyde di alkyl acetal (ABAA) according to J. of Applied Polymer Science vol. 51, 1063-1070, 1 994.
• DME dimethoxy ethanal
• ABAA amino butyraldehyde di alkyl acetal
• Another object of the invention is a process for obtaining crosslinked film at room temperature from the latexes of the invention.
• This process consists in applying either latex as it is when it is prepared in an acid medium whatever the pH of the process, or acidified latex when it is prepared in basic or neutral medium followed by a drying at room temperature or below 40 ° C, without the intervention of crosslinking agents.
• the Applicant has found that the active function in terms of crosslinking is in fact aldehyde, which can be obtained by deprotection of the acetal function in an acid medium.
• the aldehyde in the presence of water, the aldehyde is in a hydrated (non-reactive) form which will only become active again during drying and therefore filmification.
• the procedure is as follows: - an emulsion is polymerized in an acidic, neutral or basic medium, a mixture containing the monomers A and B in the proportions defined above,
• the latex obtained is brought to the pH required by the application, generally at a pH between 2 and 10.
• Each latex is then analyzed at the level of the properties of the film obtained by drying at room temperature, then of the same film after an additional heat treatment of 15 minutes at 160 ° C.
• the properties of the film evaluated are the resistance to the solvent which is determined by measurements of the percentages of insolubles of test pieces immersed in acetone at room temperature for 24 h and the percentage of acetone absorbed by these same test pieces that we call index swelling, as well as the mechanical properties of the film through a tensile test (determination of the stress and elongation at break).
• the degree of crosslinking of the film and therefore its good application properties will be characterized by the highest possible rate of insolubles, the lowest possible swelling index, as well as the highest possible stress and elongation at break.
• the latexes were synthesized in a conventional manner according to a semi-continuous polymerization process by simultaneous and separate addition of an initiator solution and a preemulsion on a base stock, previously heated to 75 ° C., located in the reactor, equipped with circulation of hot water in the double jacket, a central agitation, and a condenser.
• REWOPAL NOS 25 being an ethoxylated sodium sulfate nonyl phenol marketed by the company WITCO at 35% in water, while the
• REWOPAL HV 25 is an ethoxylated nonyl phenol marketed by the same company with 1,00% active material.
• the amounts of monomers are expressed in% by weight of active material, the Highlink DMH being sold in 50% aqueous solution by the company Hoechst (2% by weight of DMH corresponds to 1.2 mol%).
• the latexes were synthesized according to a similar process, certain syntheses having been carried out in a buffered medium, sodium bicarbonate having been, in this case, introduced into the preemulsion. Other syntheses were carried out in an ammoniacal medium, 20% ammonia having been added to the preemulsion to obtain a pH of 8, the pH in the reactor having thus been maintained above 6.
• the latexes were first of all synthesized according to a process analogous to Example 1
• the latexes are brought to pH 8 by adding ammonia and then at 45 ° C. with stirring. Dimethoxyethanal is then added in an amount less than or equal to the acrylamide stoichiometry, to lead to a DMH functionalized latex optionally having residual acrylamide functions. The reaction is maintained at 45 ° C for 7 hours with stirring. The latex is then cooled and characterized as above.
• DME is sold in a 60% aqueous solution by the company HOECHST, the amounts of Acrylamide and of final DMH being calculated by admitting a yield of the acrylamide + DME reaction of 100%.
• the latexes were synthesized according to a process analogous to that of Example 2, certain syntheses having been carried out in a buffered medium, sodium bicarbonate having been, in this case, introduced into the preemulsion.
• test pieces are 10 x 25 mm, the thickness being between 1 and 2 mm.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Paints Or Removers (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9534026

Family Applications (1)

Country Status (6)

Families Citing this family (1)

Family Cites Families (1)

• 1998
  • 1998-12-16 FR FR9815866A patent/FR2787458A1/fr not_active Withdrawn
• 1999
  • 1999-12-14 JP JP2000588234A patent/JP2003517499A/ja not_active Withdrawn
  • 1999-12-14 WO PCT/FR1999/003131 patent/WO2000035979A1/fr not_active Application Discontinuation
  • 1999-12-14 AU AU15705/00A patent/AU1570500A/en not_active Abandoned
  • 1999-12-14 EP EP99958323A patent/EP1149121A1/de not_active Withdrawn
  • 1999-12-14 CA CA002355693A patent/CA2355693A1/fr not_active Abandoned

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events