Coating process

Description of the British, Industrial and Commercial IMPERIAL CHEMICAL INDUSTRIES PLC. Patent, headquartered at Imperial Chemical House, Millbank, London SW1P 3JF, England (inventors: Eric Nield, Riaz Ahmed and Riaz Ahmed Choudhery, residing in England ) for PROCESS FOR THE COATING OF A

SURFACE USING A COMPOSITION

UNDERSTANDING A SELECTED CRYSTALIZABLE POLYMER BETWEEN POLYESTERS, POLYAMIDES AND POLYCARBONATES

DESCRIPTION

The present invention relates to a process for forming a coating using a composition comprising a crystallizable polymer in admixture with a nonreactive solvent. The composition may be in the form of a dispersion in an inert liquid or as a powder. The invention also relates to a substrate when coated by this process.

Crystallizable polymers are well known. They include polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) (these typically have a density of approximately 1.4 and

1.3 g / cm respectively), or ethylene glycol copolymers

<img file="PT98015B_D0001.tif" />

<img file="PT98015B_D0002.tif" />

and a mixture of terephthalic and isophthalic acids (FET / I), polycarbonates and polyamides (often called nylons).

A complete description of various types of polyester, polycarbonate or nylon is given in the third edition of Kirk-Othmer's Encyclopaedia of Chemical Technology published by John Viley St Sons of Sova Yorh in 1982, see volume 18, pages 549 to 574, pages 479 to 494 or pages 406 to 425 for polyesters, polycarbonates and nylons, respectively. The pages are incorporated herein by reference.

Examples of suitable polyester copolymers include polyethylene terephthalate, terephthalic and isophthalic acid copolymers and elastomeric polyesters having low glass transition temperature segments, such as polyester-polyether block copolymers some of which are commercially available from EI Dupont de Nemours under the Hytrel Trademark,

Examples of suitable polyamides are nylon 6,6, nylon 6 and copolymers thereof.

Polyamides also include newly available nylon 4, termed partially crystalline aromatic nylons. Aromatic nylons are polyamides consisting of condensates and aromatic diamines such as

1,3-Caminoethyl&gt; benzene.

Examples of suitable polycarbonates are 2,2-bis (4-hydroxy-phenenepropane CBisphenol A), commercially available polycarbonate from Anic Spa of Italy under the Trademark Sinvet.

Some of the above crystallizable polymers may acquire a partially crystalline form merely by solidification from the molten state while some notably polycarbonates and some polyesters

<img file="PT98015B_D0003.tif" />

They are amorphous as supplied but can easily be converted to partially crystalline form upon exposure to solvents. It is for this reason that polymers are generally described herein as "crystallizable" and not as "crystalline".

In general, crystallizable thermoplastic polymers have various properties such as strength, hardness, abrasion resistance and flexibility that make them potentially suitable as coating materials.

However, many attempts to incorporate crystallizable thermoplastic polymers into coatings have involved the physical milling of the polymer to form a powdered polymer, which is then blended into a liquid coating composition. These attempts have led to highly inhomogeneous structures which, due to their inhomogeneity, have shown relatively poor coating properties.

A coating composition comprised of a crystallizable polymer having improved homogeneity is described in unpublished European Patent Application No. 631 522, δ.

This Application describes a non-abrasive process for particulate production of a crystallizable polymer that contains a retained polymer solvent.

A process described therein includes dissolving the crystallizable polymer in a moderate solvent at a temperature higher than the crystalline melting temperature of the polymer when in the solvent and then allowing the solution to cool to cause solid / liquid phase separation of the solid polymer. .

The result of this process is a

3.1 dispersion in the solvent of particles of the crystallizable polymer containing the embedded solvent. The process may be carried out using a crosslinkable solvent.

Alternatively, a non-crosslinkable solvent may be used,

It is an object of the present invention to provide an alternative composition comprising a crystallizable polymer intimately mixed with a solvent not reactive with the crystallizable polymer.

According to the present invention there is provided a process for forming a coating on a surface of a substrate comprising:

&lt;i&gt; applying a layer of a composition including a polymer phase, which polymer phase includes a crystallizable polymer selected from polyesters, polyamides and polycarbonate in intimate admixture with a non-crosslinkable crystallizable polymer solvent »and &lt;ii ) heating the applied layer to a temperature at least sufficiently high to cause film formation.

The polymer phase may be in the form of a dispersion in a non-aqueous continuous diluent or may be in the form of a powder.

When the composition is in the form of a dispersion it may include liquid drops or solid particles of the polymer phase dispersed in the diluent.

Preferably the composition includes solid polymer phase particles dispersed in the diluent.

Solid means having a tack temperature greater than 605C. The adhesion temperature is measured by isolating part of the dispersed phase, for example by &lt;^ »®S! ^ Rass®! Hwws-«}

evaporating the diluent and applying a dry sample thereof on a surface having a known graduated temperature such as a Kohfler bar. A minute later, an attempt was made to remove the residue using a small soft paint brush.

The temperature above which the residue is not removable in this process is called the Tack temperature. Preferably the tack temperature is greater than 802 ° C,

The size of the droplets or particles of the polymer phase is generally from 0.1 to 500p, preferably from 0.5p to 50p.

When the polymer phase is dispersing in a non-aqueous continuous diluent the drops or particles are more preferably 0.5p to 10p. When the polymer phase is in the form of a powder, the most preferable particle size is 10 to 50p. .

Preferably, the weight ratio of solvent to polymerizable polymer in the polymer phase is 5.85 to 85:15, more preferably from 10:90 to 70:30, even more preferably from 10:90 to 50:50.

Preferably, the polymer phase includes at least 5% by weight of the composition, more preferably from 20 to 80% by weight of the composition and even more preferably from 40 to 70% by weight of the composition.

The crystallizable polymer may include a single crystallizable polymer or a mixture of two or more crystallizable polymers.

Preferably the crystallizable polymer is a polyester or a polyabornate, more preferably a polyester.

<img file="PT98015B_D0004.tif" />

A non-crosslinkable solvent is a material which may form a homogeneous solution together with the crystallizable polymer and which is not crosslinked with any of the components of the composition.

Forming a solution means that there is a temperature at or above room temperature above which the mixture of solvent and crystallizable polymer, when pure, can form a homogeneous single phase liquid solution that is clear to the naked eye. environment is generally between 1Q2 and 252C.

Preferably, the solvent and crystallizable polymer are chosen such that they can only form a homogeneous solution when mixed together by heating them above room temperature, e.g. 402 ° C, preferably 100 ° C and more preferably 18 ° C above room temperature. .

Examples of suitable non-crosslinkable solvents are dimethyl phthalate and propylene carbonate.

When the polymer phase is in the form of a dispersion in a non-aqueous continuous diluent then the composition also includes a stabilizer.

A stabilizer is a material that stabilizes the dispersed particles or drops of the polymer phase in the diluent phase to prevent or retard the deposition or flocculation of the particles or drops.

This also facilitates the formation of dispersion,

The stabilizer includes two covalently bonded components, one component that is soluble in the diluent or soluble by the diluent, referred to as the component.

<img file="PT98015B_D0005.tif" />

solvated and a second component that reacts or is associated with the polymer phase, referred to as a support component,

The nature of the solvated component depends on the identity of the continuous diluent. For example, when the continuous diluent is an aliphatic hydrocarbon then the soluble component may be a hydrocarbon chain or a polybutadiene chain.

The support component may be one that reacts with or associates with the polymer phase.

Examples of suitable carrier components that associate with the polymer phase are polar acrylate and methacrylate polymers and vinylpyrrolidone polymers.

Examples of support components which may react with the polymer phase are acid group-containing radicals, anhydride groups or epoxy-containing groups.

These types of stabilizers are well known in the art and may be selected from a wide variety of commercially available materials or produced using standard techniques.

The polymer phase may also include a non-crystallizable polymer, for example a rubber. Preferably, the polymer phase includes less than 80% by weight of the non-crystallizable polymer, more preferably less than 50% and even more preferably less than 10%.

The continuous diluent may include any non-aqueous liquid that is non-miscible with the crystallizable polymer.

This means that the polymer phase is a discrete phase when dispersing in the continuous diluent. Preferably, the diluent does not react with either component.

<img file="PT98015B_D0006.tif" />

of the polymer phase. Examples of suitable diluents are hydrocarbons, such as (C 1 -C 6 hydrocarbons).

The compositions of this invention may include other conventional coating components such as pigments, extenders, co-solvents and surfactants and other film-forming resins.

Compositions wherein the polymer phase is in the form of a dispersion in a non-aqueous diluent may be produced by a process which includes the formation of an essentially homogeneous liquid solution of the crystallizable polymer in the non-crosslinked solvent and subsequently the emulsion of this liquid solution in the diluent.

The process for producing this type of composition includes the steps of;

&lt;i&gt; formation of a homogeneous liquid solution of the crystallizable polymer in the non-crosslinkable solvent,

<img file="PT98015B_D0007.tif" />

The formation of an emulsion by emulsifying the solution in a non-aqueous continuous diluent in the presence of a stabilizer at a temperature for which the solution is a homogeneous liquid, the diluent being chosen to be non-miscivil with the temperature crystallizable polymer. to which emulsification is performed s, when the emulsion is formed at a higher temperature, at room temperature,

Allow the emulsion to cool to room temperature,

A homogeneous solution is one that is essentially clear to the naked eye. The homogeneous liquid solution of the non-crosslinkable solvent crystallizable polymer can be produced by mixing the pure polymer and the solvent

<img file="PT98015B_D0008.tif" />

jointly and, if necessary, by increasing the temperature. Generally the mixture is physically stirred, for example stirred to accelerate the dissolution process.

The solution thus can be one of two types. It may be a criticizable solution or it may be a permanently amorphous solution.

Crystallizable solutions have a crystalline melting temperature of the polymer in the solution,

The crystallizable polymer may be produced by recrystallization from such a solution if the solution is slowly cooled to a temperature above its Crystalline Melt Tm temperature.

Solutions that are permanently amorphous do not have a Crystalline Fusion temperature. The crystallizable polymer cannot be produced by recrystallization of Permanently Amorphous solutions,

The crystalline Melting Temperature &lt;Tm&gt; of the polymer in the solution can be determined by differential scanning calorimetry &lt;DSC&gt;. The method for determining the Tm for the polymer in any given solution first involves determining the Crystalline Melting Point &lt; Tm&gt; for pure crystalline polymer. The Tm value for the pure crystalline polymer is then used to determine the Tm for the solution.

Tm values ​​for a large number of known polymers are available in the literature. Alternatively, the Tm for any crystallizable polymer may be determined experimentally.

To experimentally determine the Tm for the pure polymer, a test cycle was performed in which 10 mg of the polymer was heated in a DSC machine at 2852 ° C to a speed of 202 ° C / min and subsequently cooled.

<img file="PT98015B_D0009.tif" />

at a speed of 202 G / mitt to room temperature. Tm, if present, is seen as an endothermic psycho on the heat graph, absorbed as a function of temperature as the temperature increases.

Certain crystallizable polymers or mixtures of crystallizable polymers have more than one endothermic peak. In such houses the Tm is considered as the maximum peak in temperature.

Certain crystallizable polymers do not exhibit an endothermic peak due to Tm during the test cycle. This is because they are in an amorphous meta-stable stay when supplied. In this case, the polymer is converted to a crystalline state and the assay is then repeated. The crystallizable polymer may be crystallized upon contact with a suitable solvent, such as a lower molecular weight ketone, for example acetone or methyl ethyl ketone, to cause crystallization. The test cycle is then repeated and obtained. if a value for Tm.

In order to determine the Tm for the solution under analysis, a test solution was made by heating the desired mixture of pure crystallizable powdered polymer with a particle size of less than 250μ and solvent with stirring at a temperature of 2 ° C. above Tm of pure polymer. The test solution was kept at this temperature for 5 minutes before allowing to cool to room temperature.

The test solution was subjected to a test cycle in which 10 mg of the DSC solution was heated to a temperature of Tm for the pure polymer at a rate of 20 c / min and subsequently cooled to room temperature. at a speed of 2Q2 C / min,

Again, as with the polymer Tm

IO -

<img file="PT98015B_D0010.tif" />

pure, Tm was seen as an endothermic point on the graph of heat absorbed as a function of temperature and when more than one peak appears, the Tm value is taken as the highest peak value.

Certain mixtures do not have an endothermic peak due to Tm in the heating / cooling cycle. When no endothermic peaks arise, a fresh sample solution is annealed by heating at an annealing temperature at this temperature for 1 hour. Annealing temperature is defined with reference to Ta of pure crystallizable polymer. Annealing temperature is less than 80 ° C at Tm of pure crystallizable polymer.

An additional heating / cooling cycle is then performed. If no endothermic flooring is observed, fresh samples are annealed to

2,3,4 and 5 hours after which a heating / cooling cycle is performed.

As soon as an endothermic peak arises, then Tm value is recorded for this cycle. If after five hours of annealing at this temperature a peak does not yet appear, then the annealing procedure is repeated at a temperature below 100 ° C at Tm. pure polymer.

If after 5 hours at 8 ° C below the pure polymer Tm and 5 hours at 1 ° C below the pure polymer Tm no peak still appears, the mixture is referred to as having no Crystalline Fusion temperature Tm. The resulting solution is referred to as a Permanently Amorphous Solution *

When measuring a Tm, then recrystallization of the polymer from the solution may occur at or above room temperature. The resulting solution is then referred to as a crystallizable solution. Preferably the solution is a crystallizable solution.

.&lt;*·

Preferably the crystalline melting temperature of the polymer in the solution is above 10 ° C, more preferably above 1302 ° C and even more preferably above 150 ° C.

emulsifying step (ii) may be performed using conventional emulsifying apparatus such as a high speed stirrer or ultrasonic spreader. A particularly convenient high speed stirrer is a Silverson high speed stirrer available from Silverson LTD,

Emulsification can be performed by first adding the solution to the diluent and then applying the shear force using the emulsifying apparatus. Alternatively, the shear force may be initially applied to the solution or continuous diluent and then added to the other component slowly. An additional possibility is to first form a mixture of polymer, stabilizer, solvent and diluent and then apply the shear force to this mixture to which the polyasomer can dissolve in the solvent.

When the crystallizable polymer and the non-crosslinkable solvent may form a homogeneous solution to. at room temperature, then the emulsion step may be carried out at room temperature or above.

When the crystallizable polymer and non-crosslinkable solvent can only form a homogeneous solution at elevated temperatures then the emulsion is carried out at or above that elevated temperature.

When the solution is crystallizable, the morphology of the dispersed polymer phase at room temperature depends on the rate at which the emulsion is allowed to cool to room temperature.

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Generally, if the emulsion is allowed to slowly cool then recrystallization of the crystallizable polymer can take place and the resulting composition includes a dispersion in which the polymer phase contains recrystallized polymer. Slowly means at a speed not exceeding 202 C per minute, for example 12 C per minute.

Rapid cooling of the emulsion results in a dispersion of the particles or drops in an amorphous state. Rapid cooling usually means at a speed greater than 502 C per minute.

The size of the droplets or particles of the polymer phase depends on the viscosity of the solution at the temperature for which the emulsion step is performed, the degree of agitation and the amount of stabilizer used. A lower solution viscosity, a high degree of agitation and a larger amount of stabilizer can produce the increase of smaller droplets or particles.

Preferably, the crystallizable polymer is chosen such that it dissolves or softens again in the solvent during film formation after evaporation of any diluent and at the temperature at which film formation occurs.

When the polymer phase is in powder form this can be done by separating the solid particles from the polymer phase from the continuous diluent phase of a dispersion as described above.

The dust is isolated by the steps of;

isolating the solid polymer phase particles from the composition produced in step (iii), and allowing the isolated particles to dry to remove the diluent

The particles of the obtained polymer

V¹· Contain retained non-recyclable solvent.

Optionally the isolated particles may be washed with a liquid other than a particulate solvent to remove any unwanted residue from the continuous phase.

The particles may be isolated by filtration or by centrifugation. Filtration may be accomplished by passing the emulsion through a filter medium, for example paper or sintered glass.

Preferably, the polymer phase particles have a size of IG-Sqp when it is desired to isolate them by the modified process. Particles in this size range are easily isolated and are of a size suitable for use in coating applications.

A retained solvent containing powder has been found to have improved flow properties when used in powder coating applications.

In a further modification of the process, the particles may be subjected to a solvent removal step in which the retained solvent is removed from the particles, for example by extracting the particles and evaporating the remaining solvent in an oven. These polymer particles with or without retained solvent may be redispersed in a liquid carrier to form a redispersed particle composition which is a liquid composition containing the redispersed particles.

liquid carrier in which the particles are redispersed may be the same as the continuous diluent from which the particles are isolated or may be different,

Preferably he is different. The liquid carrier may, for example, be a composition of

<img file="PT98015B_D0011.tif" />

coating that may be based on an organic solvent or water. Coating compositions typically include a film-forming polymer and a liquid diluent.

Typical binders for coating compositions are described in the third edition of the book Introduction to Point Chemistry by GPA Turner published by Chapman and Hall of London in 1988.

particles may be redispersed under lower shear conditions _s for example by agitating the particles in the liquid carrier.

The compositions may be applied to the substrate by conventional application means. Examples of conventional application means for liquid compositions are brushing, spraying, dipping or roller coating. An example of a conventional powder application medium is electrostatic spraying.

Typically, the applied layer is heated to a temperature of from 50 ° C to 30 ° C, most commonly from 15 ° C to 25 ° C. The layer is typically heated for approximately 15s to 15 minutes to allow film formation.

The coated surfaces according to this invention may be metallic, for example aluminum, stainless steel or non-metallic, for example glass, wood, paper or textile. The composition may be used to impregnate continuous fabrics of a wide variety of fibers including glass and carbon fibers by surface application of the fibers. The impregnated fibers may be molded during curing to produce a composite material which upon cooling includes fibers consolidated in the cured solvent.

In particular the composition may be used for coated sheets, especially coated sheets.

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Metal for use in molding processes) and molded articles such as cans, for example, food or beverage cans.

The invention also provides a substrate when coated by the above process,

The process may also be used to form free films, i.e. unsupported composition sheets to adhere to a substrate.

These sheets can be made by first forming a coating cured by the above process, followed by the disintegration of the substrate coating,

The invention will then be illustrated by the following examples:

ES £ J £ ELQ§.

The following dispersant was used in the production of compositions according to the invention.

Charge 1

Toluene

Polybutadiene (Lithene (Q4 5000))

White Alcoholic Drink

396.14

199.74

197.74

Lithene is a Registered Ark of Revertex

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_M f __ ^ τνΛ'ΎΓΓνν, ν7ν^,Π ^ «·· ~ {?^:; «. ·, 'Ν ·' U rjn.íXTíàUii ^ * ··· ^ '

Charge 2

Methyl Methacrylate 137.74

Methacrylic Acid 11.93

Lucidol P 25 (Benzaila peroxide containing 25% water) 5.33

Charge 2 was added for 1.5 hours at Charge 1 at 120-225 ° C at reflux temperature. After an additional 0.5 hours, 1.33 parts of tert-Butyl trigonox 21B 70 Cper-2-ethylhexanaate is added, Trogonox is a Segmented BRAND. Chemicals) and heating was continued for an additional hour. The solvent (99.1 parts) was stirred by distillation and replaced with an equal volume of white alcohol. The product was opalescent with a viscosity of 0 ° C. 0.5 to 1.0 Pas and a measured solid content of 37%,

COMPSSI ^ SS.

Coffigaslçges ia, &amp; £ ·

Compositions 1 to 4, 5B and 6B show the preparation of various compositions according to the invention.

Compositions 5A and 6A are comparative compositions having no non-crosslinkable solvent. Compositions were produced according to the following method using the components set forth in Table 1, AT® for each composition, the dispersion size and range for each of them are presented together in Table 2,

Method.

The polymer and solvent were heated to temperature TÂ ° for which a homogeneous solution was obtained.

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This solution was added to a mixture of the inert diluent and any dispersant which had been preheated to 2002 ° C.

The solution was emulsified in the diluent using a laboratory homogenizer (Silverson L2R produced by Silverson Machines Ltd of Chesham, UK) equipped with a &lt;0.5 mm fine mesh). The emulsification was sealed by dipping the homogenizer head into the diluent mixture, turning the homogenizer to full power &lt;apr. 9000 rpm) and then adding the solution over a period of 1-2 minutes and maintaining the emulsion temperature at approximately 220 ° C. The emulsification was continued for a further five minutes. The resulting milky emulsion was cooled using an ice-water bath while halogenizing the power of the homogenizer (ca. 5000 rpm) until the temperature reached 6020 ° C. The cooling rate was 202 - 30 ° C / min in each case. The homogenizer and the ice bath were removed and the composition allowed to cool to room temperature (approximately 2020 ° C).

Table 1 shows the components for Compositions 1 to 6B which were all produced according to the Method given above. The percent Dispersant is by weight, nonvolatile, of the tofcal weight of the crystallizable polymer plus the solvent. The abbreviations used in the tables are as follows:

Crystalline golimeros.

Pet is a heteropolymer of ethylene glycol and terephthalic acid, with an intrinsic viscosity of 0.64 to 0.66 cmS / g in ortho-chlorophenol at 25 ° C,

PET / I is an ethylene glycol capillary and a mixture of terephthalic acid and isophthalic acid at a ratio of 82:18, with an intrinsic viscosity of 0.63 to

<img file="PT98015B_D0013.tif" />

0.65 cm @ 3 / g in ortho-chlorophenyl at 25Â ° C.

PBT is a butylene terephthalate hamopolymer available from Atochen under the Trademark Orgater TSK O,

PC- is a polycarbonate available from Anic Spa. Of Italy under the Trademark Sinvet 251, solvent used was dimethyl phthalate.

Dispersant A was prepared as previously described.

Siluastas.

Diluents used were aliphatic hydrocarbons available from Exxon Chemicals under the Trademark Exxsol D100, and Exxsol D14Q.

<td>Comp.</td><td>Polymer Crystallizable</td><td>Solvent</td><td>Dispersant THE</td><td>Diluent Inert</td>

<td> 1</td><td>ΡΕΤ / Σ &lt;80g&gt;</td><td>20g</td><td> 8%</td><td>I say &lt;100g&gt;</td>

<td> 2</td><td>PRAÇA</td><td>36g</td><td>and%</td><td>I say</td>

(30g&gt; &lt;100g&gt;

<td> 3</td><td>PET &lt;45g)</td><td>32g</td><td> 8%</td><td>I say &lt;100g&gt;</td>

<td> 4</td><td>PBT</td><td>12g</td><td> 8%</td><td>I say</td>

<td></td><td>&lt;48g&gt;</td><td></td><td></td><td>ClOOg&gt;</td>

<img file="PT98015B_D0014.tif" />

<td>5A</td><td>PBT &lt;35g&gt;</td><td>Sweetness</td><td> 8%</td><td>DL 40 &lt;150g)</td>

<td>5B</td><td>PBT &lt;35g)</td><td>10.5g</td><td> 8%</td><td>DL 40 &lt;139g&gt;</td>

<td>6A</td><td>ΡΕΤ / Σ &lt;30g&gt;</td><td>None</td><td> 8%</td><td>D140 &lt;130g)</td>

<td>6B</td><td>PET / I &lt;30g)</td><td>ios</td><td> 8%</td><td>DL 40 &lt;120g)</td>

You. and size and range of the dispersion for the pharmaceutical compositions in Table 1. The size and range of the dispersion was measured using an optical microscope.

Composition T “Dimension Range Average Dimension

Dispersion particle &lt;p&gt; ζμ)

<td> 1</td><td> 220</td><td> 70</td><td> 40-100</td>

<td> 2</td><td> 240</td><td> 40</td><td> 4-60</td>

<td> 3</td><td> 250</td><td> 20</td><td> 4-60</td>

<td> 4</td><td> 230</td><td> 20</td><td> 10-100</td>

<td>5A</td><td> 240</td><td> 5</td><td> 1-10</td>

<td>5B</td><td> 240</td><td> 25</td><td> 5-50</td>

<td>6A</td><td> 220</td><td> 40</td><td> 2-55</td>

<td>6B</td><td> 220</td><td> 10</td><td> 1-20</td>

<img file="PT98015B_D0015.tif" />

Bavarian acts. -... Examples, ..CQfflpar.afivQg,

Compositions 5 A and 5B were applied to aluminum panels &lt;300 mm x 100 mm x 0.9 mm&gt; by means of a "K-bar". K-Bars are stainless steel bars, wrapped with stainless steel wires of selected diameters, to produce predetermined wet film deposits. CK-bars ”are provided by SE Print-Coat Instruments htd, Royston, Herts &lt;UK&gt;.

The panels were heated in an oven at 250 ° C for 3 minutes and then cooled immediately by soaking the panels in a room temperature water bath. The resulting coatings were clear and smooth with film thicknesses between 30-33p. Coatings were subjected to a Reverse Impact Test according to ASTM Test D 4145-83 (Resistance of Organic Coatings to the effects of Rapid Deformation.) Coatings from composition 5A were found to have an impact strength of less than 5%. Ib-in while those from 5B are able to counter impacts greater than 40 Ib-in.

Compositions 6A and 6B were applied to aluminum panels and heated at 21 ° C for 3 minutes. The resulting coatings derived from composition 6A were brittle, poorly coalescent while those derived from 6B were soft and smooth,

Coatings using aqueous disper-S &amp; gs Preparation of non-aqueous dispersion of Epikote 880. Epikote 880 was emulsified with a biphenol A / epi-chlorohydrin type epoxy resin of epoxide equivalent weight 182-194. available from Shell Chemicals, 92g&gt; Dispersant A &lt;21.6g&gt; and Exxsol D100 &lt;100g&gt; together using a Silverson high speed stirrer. The milky emulsion consists of medium sized fine droplets of approximately 1 micron.

&lt;ii&gt; The above dispersion &lt;i&gt; &lt;20g) was mixed with Synprolam 3553 (an available diamine resin from ICi Flc, 10g&gt; to produce Composition 7. Epikote 880 5AD &lt;6g&gt; was mixed with 20g of composition 6B { see Table 1&gt; and Synprolam 3553 C3g&gt; to produce composition 8.

Compositions 7 and 8 were applied to aluminum panels (300 mm x 100 mm x 0.0 mm) using K-bar number 8 and heated at 23 ° C for 15 minutes.

The resulting coating was soft and smooth with 25p film thickness. The resultant derivatives of composition 7 were opposed to double MEE friction of 10 whereas the coating of composition 8 was opposed to a double MEE friction value of 20. The Reverse Impact Test on coatings revealed that up to an impact of 5 The composition 7 is released and removed from the aluminum substrate while the coating of formulation 8 remained intact.

SUELI,

JLÇULL &amp;

11. A process for forming a coating on a surface of a substrate, characterized in that: applying a layer of a composition comprising a polymeric phase which comprises a crystallizable polymer selected from polyesters, polyamides, and polycarbonates, in admixture with a non-crosslinkable solvent for the crystallizable polymer, and ii) heating the applied layer is at a temperature at least high enough to provide film formation,