CA1148038A - Resin coated wooden articles and method of coating - Google Patents

Abstract

RESIN COATED WOODEN ARTICLES AND
METHOD OF COATING

ABSTRACT

Prepolymerized resins are applied to wooden articles to coat them and impart a tough and abrasive resistant surface which protects the articles from deterioration and delamination due to shock, impact and abrasive forces. The resins are applied by contacting the articles with a prepolymerized resin which has been dissolved in a readily vaporizable solvent to form a resin solution, coating the article with the resin solution, vaporizing the solvent from the resin coating and drying the resin coating. The coated articles find particular utility in high shock and impact uses such as hockey stick blades.

Description

.j ~
` '-\ l i 114~3~3 BACKGRO~ND OF T~E INVENTION

¦I T~e present invention relates to wooden articles having i! a protective resin coating, the resin coating and to a method of applying the coating to the articles. The resin imparts to the coated wooden articles a tough and abrasive resistant pretective surface. The invention particulàrly relates to applying pro- ¦
tective resin coatings to wooden articles which in normal use are subjected to moisture and high shock, impact and abrasive forces. The resin coating effectively protects the coated I~ articles from deterloration, damage and delamination due to Ii moisture and abrasive, shock and impact forces. More particu- I
, larly, the invention relates to a method of applying a prepoly- ¦
merized resin to wooden articles which comprises contacting the ¦~ wooden articles with the resin, coating the articles and drying iI the resin in such manner that the articles can be further pro-,jcessed or packaged a short time after application of the resin.
The preferred prep~lymerized resins are the commer-cially available phenoxy and polyamlde reslns. Mixtures of these resins with each other or with other compatible resins can ¦also be used.
20 II The invention finds particular advantageous utility in the manufacture of hockey stick blades, golf club heads, asebal1 bats and bowlLng p1ns.

I

.11 _ , r ` :

8~3 I
l PRIOR ART

¦I The use of polymerizable resins and certain polymerized ~
¦ resins for impregnating and/or coating wooden articles to provide j a protective surface on the articles is generally Xnown. For example, the wooden blades of hockey sticks have been coated with polymerizable epoxy resins to provide a protective coating ¦ on the hockey stick blades. The use of polymerizable epoxy resins, however, requires relatively di~ficult means of applying ¦ the resins, polymerizing the resins on the hockey stick blades ¦¦ and relatively long periods of time for curing the resins.
~ Another means for protecting hockey stick blades has been simply to place a protective resin sleeve over the blade which increases , ¦ its mechanical strength (U.S. PATENTS 2,912,245; 3,353,826 and 3,458,194).
ll Wooden golf club heads have been taught to be protected 1 in U.S. Patent 2,936,248 by impregnating the heads with vlnyl ¦¦ resins to make them resistant to deterioration due to absorbing moisture. The described process, however, requires a prolonged impregnating step, the use of two solvents and a prolonged two-step drying procedure employing relatively high temperaturès.
A method for protecting the ball impact belly of wooden bowling pins is disclosed in U.S. Patent 3,024,819 and comprises a procedure of coating the belly of the bowling pin with en epQxy or nylon resin and mechanically compressing the ¦belly portion of the pin to compress and densify the belly portion of the pin ~nd then allowing the resin to ~et.

Ij ~8~
Still another method of protecting wooden articles is disclosed in U. S. Patent 3,712,659 and comprises simply pro-viding the handles of wooden articles such as manual work tools and sports implements with an epoxy resin coating. It is noted that the U. S. Patent 3,712,659 does not disclose any specific method or conditions for coating the described articles. ~:
The above-mentioned prior art methods generally exhibit several process disadvantages such as requiring pro-longed impregnating and curing steps and/or one or more dryingsteps at relatively high temperatures.
SUMMARY OF THE INVENTION
The present invention relates to new and improved wooden articles having a protective resin coating which pro-vides a tough and abrasive resistant surface to the articles.
The coated articles are resistant to moisture and are resis-tant to abrasive damage and damage due to high shock and impact forces. The invention is particularly useful in the manufacture of wooden articles which in normal use are subject to abrasive, high shock and impact forces such as hockey stick blades, golf club heads, baseball bats and bowling pins. The applied resin coating renders the surface of the coated ar-ticles impervious to moisture and resistant to damage due to abrasive, shock and impact forces.
In accordance with a broad aspect of the invention, there is provided a wooden article having at least an impact area protected with a 0.1 to 0.5 mm thick coating of es-sentially a prepolymerized phenoxy resin of the formula [ , ~ - C __ ~ o-CH2 - ICH CH2]n C

wherein n = 150 to 700 and having a molecular weight of from 45,000 to 200,000 or prepolymerized polyamide resin having a molecular weight of 5,000 to 10,000 or mixtures thereof.
In another aspect of the invention, there is pro-vided a method of applying a protective phenoxy or polyamide resin coating to a wooden article, which method comprises con-tacting said article for about 1 to 90 seconds with a coating solution consisting essentially of a prepolymerized phenoxy resin of the formula I--O--~_C~ --C~2--1~C~2]n wherein n = 150 to 700 and having a molecular weight of from 45,000 to 200,000 or prepolymerized polyamide resin having a molecular weight of 5,000 to 10,000 or mixtures thereof dissolved in a readily vaporizable solvent, coating the article with the resin solvent solution, withdrawing the article from the resin solvent solution and drying said coated article in about 5 to 30 minutes by vaporizing the solvent from the resin coating on said article to obtain a 0.1 to 0.5 mm thick resin coating that is nonsticky to the touch.
Thus, the invention relates to a simple inexpensive method of providing a protective resin coating on - 3a -.~

; . .

!! . ... I
i wooden articles which comprises dissolving a prepolymerized ¦I resin~ i.e., preformed resin such as phenoxy resin or polyamide Il resin, in a readily vaporizable solvent, contacting or immersing i! the article with or in the solvent, vaporizing the solvent and ' drying the article. Minor amounts o~ less volatile solvents, such as cellosolve acetate, may be incorporated with the more ¦ volatile solvents to control the rate of evaporation and permit a uniform coating of the wooden obJect with minimum "drips".
Ii The entire process requires only a few minutes. After drying, 1i the articles are ready for further processing, shipment or use.
The use of the prepolymerized resins and readily l, vaporizable solvents as a means for applying a protective resin ! coating provides an inexpensive method of application which can li be carried out in a short time, in simple process equipment '' without heating or curing steps and without difflculty. The ,I tough adherent resln coating obtained protects the wooden !! articles and substantially increases the useful life of the articles, for example hockey stick blades, under actual use, i.e~, game conditions.
.' DETAILED DESCRIPTION OF THE INVENTION
!
In accordance with the invention, wooden articles are immersed in a bath of the coating solution containing a pre- ¦
polymerized resin, such as phenoxy resin or an amorphous poly-amide resin, dissolved in a readily vaporizable solvent, such as a ketone, Iow molecular weight aliphatic alcohol, an aromatic ! .
~ Trade ~ark "

1, .
--- B~

~ ;,. I

i - !
1,l ¦l or chlorina~ed hydrocarbon solvent, at about ambient temperature and pressure for about 1 to 60 seconds to allow complete wetting and coating on the articles. The coated articles are removed from the bath and the solvent evaporated therefrom and are dried in about 10 to 20 minutes and at about ambient temperature and ¦ pressure. The articles after drying are substantially free of ¦~ solvent, are smooth, hard and nonsticky to the touch.
The thickness of the resin coating depends on the par-I ticular resin and physical properties of the resin used and the ¦ solvent and amount of solvent used and can be about 0.1 to 0.5 mm thick. The time for vaporizing the solvent and drying the resin coating depends to some e~tent on the amount and the solvent used and the resin used, the resin coating thickness and l the solvent vapori~ation temperature and pressure.
The wooden articles intended to be coated in accordance with the present invention are those articles which in normal use are subjected to frequent abrasive contacts with other materials and high shock and impact forces. The entire article may be coated or only an impact area of the article may be coated.¦
In one embodiment of the invention, hockey stick blades made from ash, maple or rock elm woods are coated with a pro-tective resin.
In another embodiment of the inven$ion, wooden golf club heads made from persimmon, maple or rock elm woods are ¦ coated with a protective resin.

_ ~8~38 ;I , In still another embodiment of the invention, baseball bats made f~om ash, maple or hickory woods are coated with a ! protective resin.
,1 In still another embodiment of the invention, bowling 5 11~ pins made from maple wood or a composite of maple wood bonded together, white ask or rock elm woods are coated with a pro-Il tective resin.
Il The prepolymerized polymer resins which are used arethoe with sufficient polarity to adhere well to wood and which o !~ can be prepared in a manner such that the coatings or films are water impervious, tough, abrasive resistant and resistant to high shock and impact forces. The prepolymerized resins can comprise, for example, phenoxy resin or phenoxy resin and up to 20~ to 25~ by weight of other compatible prepolymerized resins I such as polyurethanes and thermoplastic polyurethanes, cellulosic I
esters, polyvinyl butyral, and styrene-butadiene block copolymer, I
thermoplastic styrene-butadiene-styrene and styrene-isoprene-styrene block copolymers. The prepolymerized resins can also Il comprise thermoplastic polyamides which are soluble in alcohol 20 1l or alcohol mixtures. These noncrystalline polyamides are also known as "fatty polyamides" since the acid components are the so-called dimer acids. The polyamides can be used with minor amounts of other compatible resins, such as polyurethanes and l¦cellulosic esters. The prepolymerized resins that are used in 1the present invention are soluble in readily vaporizable solvents.

I

( ~
1~48~)38 . , Preferred prepolymerized resins are phenoxy resins, suchl *
as PKHH, produced and sold by Union Carbide Company and which consists of the following repeating unit:
.

t_ O ~ O - Cl~ - CH C~2 ]n ; CH3 OH

wherein n has a value of about 150 to about 700 and Eponol resins Il produced and marketed by Shell Company which consists primarily !! i ' of the same chemlcal composition in a suitable sol~ent. The ,~ thermoplastic polyurethanes, such as Estane 5702 produced and marlceted by B. F. Goodrich Co., can be used with phenoxy reslns.
, The chemical composition and physical characteristics of I suitable phenoxy resins are given in Table I below.
'! i I T~BLE I
'I PHENOXY COATING RESINS
' N~me( ) Solid Content (~) Molecular_W~ ht Visc~cp) Il i I i ¦I Eponol 52-B-40 40 45,000 1218 53-B-40 40 80~000 2800 ll 55-B-40 40 200,000 9800 i a. Eponols are manufactured by Shell Chemical Co., PKHH
j is manufactured by Union Carbide Chemical Co... Other !Imanufacturers of phenoxy resins include Ciba Products Co. and Dow Chemical Co.

, * Trade Mark 1. 1 '' . I
~ _.L ` I

-11~8V38 , The polyamides that can be used in the present inventior include ~he Versamide and Versalon polyamides produced and marketed by General Mills Chemical, Inc. of Minneapolis and I the Emerez polyamide resins produced and marketed by Emery , Industries, Inc. of Cincinnati.
The principal physical characteristics, such as soften-ing point and viscosity, of specific polyamide resins that can be used are given in the following Table.

,1 I TABLE II
10 li POLY~M DE COATING RESINS
Revers j Impact Polyamide So~t Pt(C)b Mol. Wt.C Visc(~oise-TemP~oc)(in/

i Versamide ~65 176 low 9 138 70 Versalon 1124 124 medium 38 171 80 Versalon 1300 95 medium 46 210 160+

il Versalon 1138 140 medium 46 210 160+

Il Emerez 1565 99 low 14 160 1~0+

~! ~merez 1553 110 medium 100 190 160+
.1 , a. Emerez resins are produced by Emery Industries, Inc., the I Versamide and Versalons ~rom General Millso 20 ¦I b. Approximate e. Range is ~rom about 5000 to about 10,000.

Il ' * Trade Mark .

_1~ . ......... ~

1~8~38 Various conventional plasticizers and other additives such as leveling agents, thickening agents, dyes and fillers can be added to the resins to affect the flow properties, color and lphysical properties such as hardness, resilience, tensile strength, ¦impact resistance and flexual modulus.
The phenoxy resins can be dissolved in readily vaporizable ¦¦solvents such as acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, toluene, cellosolve acetate, and mixtures l thereof.
~ The polyamide resins can be dissolved in readily vaporizable~
aliphatic alcohol solvents containing 1 to 8 carbon atoms, par-~ticularly aliphatic alcohols containing 3 to 6carbon atoms and jmixtures thereof, or mixtures of said alcohols with aromatic sol-lvents such as toluene, xylene, benzene, aliphatic solvents such as pantane, hexame, heptane and octane, and chlorinated hydro-carbon solvents such as 1,1,2-trichloroethylene and/or mixtures thereof. Specific alcohols that can be used are propyl, butyl, pentyl and hexyl alcohols. A mixture of an alcohol and hydrocarbon lis preferred.
Depending on the wooden article to which the resin is to ~e applied, the resin solvent composition can contain 5 to 50%
y weight, preferably 10 to 40% by weight and more preferably 15 ~o 30% by weight of the prepolymerized resin. The resin solvent Isolution can be applied to the wooden article to be coated by ~I mersing the article in a bath containing the resin solvent olution, by spraying the article to be coated with the resin solvent solution or by other suitable coating methods.
! In a preferred embodiment of the invention the wooden ~rticles are immersed in a resin solvent bath for 1 to 90 seconds, ll ,, _ g _ !
8~38 preferably 1 to 60 seconds and preferably 2 to 30 seconds at a temperature of 15 to 40 C., preferably 20 to 30 C and more preferably at about ambient temperature. Longer immersion l times can be used but are not required, preferably the minimum ¦ time required to obtain complete wetting of the object is used.
¦¦ The immersion step can be carreid out at reduced or elevated , pressures~ but ambient pressure is preferred.
Il After immersing the wooden article in a resin solvent solution bath, wetting and coating the article with the resin solution, it is removed from the bath and allowed to drain free li of excess solution and the solvent vaporized therefrom in about I
~ 2 to 40 minutes, preferably 5 to 30 minutes and more preferably ¦
10 to 20 minutes at a temperature of 10 to 40C., preferably 15 to 30 C., and more preferably at about ambient temperature.
, The drying step can be carried out at super or sub-atmospheric pressure, but is preferably carried out at ambient pressure.

¦ EXAMPLES
¦ The novel wooden articles of the present invention and the process of making them are illustrated by way of the following examples which are not intended to limit the invention.

ll EXA~PLE 1 A hockey stick with a blade made of white ash wood is immersed in a resin solvent solution coating bath containing 1250 grams of PKHH phenoxy resin dissolved in 5 liters of 80:20 MEK-toluene solvent to make a bath containing 25~ by ¦--l~ weight of the phenoxy resin, at a temperature of about 25 C0 25 1l at which the solution has a Brookfield viscosity of about 400 cp.
, i, 1148{)38 i! The hockey stick is held in the bath for 20 seconds after which it is ~emoved and the solvent vaporized at a temperature of iabout 25 C for about 10 minutes. The hockey stick blade is now lldry and essentially free of solvent, has a toughj hard, smooth Iresin coating about 0.2 millimeters thick which is nonsticky to the touch.
`I EXAMPLE 2 ¦; A wooden gol~ club head made of persimmon wood is llimmersed in a resin solvent solution coating bath containing 3000 Ilgrams of Eponol 55-40B phenoxy resin, which is a 40% by weight ,solution of 200,000 molecular weight phenoxy resin dissolved in .8 liters of mixed solvent consisting of 3:2:1 by weight of ~EK, toluene and cellosolve acetate to make a bath solution containing 25~ by welght phenoxy resin, at a temperature of 25G.
at which the solution has a viscosity of about 500 cp and is held Ithere for one-half minute after which it is removed and the solvent ,~aporized at a temperature of about 25 C. for about 10 minutes Ihe dried golr club head has a tough, hard, smooth resin coating ¦.15 millimeters thick which is nonsticky to the touch.

~ AMPLE 3 i ¦ A baseball bat made of white ash wood is immersed in a resin solvent solution coating bath containing 300 grams of PKHH
~henoxy resin and 100 grams of prepolymerized polyurethane polymer resin, Estane 5702, dissolved in 1.6 liters of solvent (4:1 MEK-llolune) to make a bath containing 20~ by weight of the resins, at ~ temperature of about 25 C. at which the solution has a Brookfield .,1 1 ! ¦
,1 i , _ . : I . . . ... . . . ... .

~ \ `I ii : ~148i:~38 ", .` ................. , 1, "
viscosity of 500 cps. and held there for one minute after which it is removed and the solvent vaporized at a temperature of about 25 C. for about 10 minutes. The dried baseball bat has a tough, I hard, smooth resin coating 0.1 millimeters thick which is non-sticky to the touch.
, EXAMPLE 4 A bowling pin made of portions of maple wood bonded together is immersed in a resin solvent solution coating bath l~containing 875 grams of PKHH phenoxy resin dissolved in 2.6 Illiters of mixed solvent (consisting of 2300 cc MEK, 50 cc butyl cellulose and 450 cc cellulose acetate) to make a bath containing 36~ by weight phenoxy resin, at a temperature of about 25 C. at which the solution has a viscosity of about 1000 cp and held there for 10 seconds after which it ls removed. It is then dried ~by vaporizing the solvent at a temperature of about 25 C for about 20 minutes. The dried bowling pin has a tough, hard, Ismooth resin coating 0.25 millimeters thick which is nonsticky to the touch.

1l A hockey stick made of a maple wood blade and a white ,lash handle is immersed to a depth of approximately 18 inches to completely cover the blade and part of the handle, in a solution ¦~ade of 20 parts Versalon 1138 polyamide resin and 80 parts of ¦!75 25 isopropyl alcohol-toluene solvent at a temperature of about ~25 C. at which the solution had a Brookfield viscosity of 500 cps.
Il , Il '. I

__ , _ _ ~148~38 .

After 3 seconds immersion, the stick was removed and held above the dripping bath for 2 seconds to allow excess liquid to drain back into the bath and then placed on a rack with the heel ,portion of the blade down for 10 minutes at 25 C. to dry. The Ijhockey stick, after the 10 minute drying time, is essentially free of solvents, has a tough, hard, smooth resin coating approximately ~0.15 millimeters thick which is nonsticky to the touch. A
,IGardner impact test made 24 hours after drying revealed no Iseparation of the coating nor any significant damage at an l~impact of 60 inch-pounds.
., I! EXAMPLE 6 ! A hockey stick similar to the stick of Example 5, except that the portion to be coated had a fiberglass fabrlc bonded to the blade using an epoxy resin, was immersed in a Iresin solution made of 30 parts Emerez 1533 polyamide and 70 parts 75 :25 isopropanol-heptane solvent for 5 seconds at 25C.
The stick was removed from the bath and allowed to drain for

2 seconds and then placed on a rack for 10 minutes at 25 C to Idry. After the 10 minute drying, the hockey stick blade is 1 essentially free of solvent, has a tough, hard smooth resin coating approximately 0.3 millimeters thick which is nonsticky to the touch. The bath had a Brookfield viscosity of 200 cps.
The dried smooth resin coating adhered extremely well both to llthe fiberglass-epoxy laminate portions of the stick and to the i,exposed wood portions. A Gardner impact test made 24 hours ~fter drying revealed no separation of the coating nor any 1, ~ . .. . . . ... .. .

11~8~38 ,1 .: ........................ I
significant damage to an impact of 60 inch-pounds.
The above-described coated wooden articles can be immediately further processed, packaged and/or used.
The invention has been described with respect to ~ various specific illustrations and examples thereof which are I not intended to be limitative since it is evident to one skilled in the art how modifications can be made, equivalents employed and substitutes utilized without departing from the sp1rit snd scope oP the lnvention.

_ ....... .. i.. _ . _ _ .

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of applying a protective phenoxy or polyamide resin coating to a wooden article, which method comprises contacting said article for about 1 to 90 seconds with a coating solution consisting essentially of a prepolymerized phenoxy resin of the formula wherein n = 150 to 700 and having a molecular weight of from 45,000 to 200,000 or prepolymerized polyamide resin having a molecular weight of 5,000 to 10,000 or mixtures thereof dissolved in a readily vaporizable solvent, coating the article with the resin solvent solution, withdrawing the article from the resin solvent solution and drying said coated article in about 5 to 30 minutes by vaporizing the solvent from the resin coating on said article to obtain a 0.1 to 0.5 mm thick resin coating that is nonsticky to the touch.

2. The method of claim 1 wherein the wooden article is contacted with the resin solvent coating solution for about 1 to 60 seconds at a temperature of 20° to 30° C.

3. The method of claim 1 wherein the wooden article is dried and the solvent is vaporized and removed during a period of about 2 to 40 minutes at a temperature of 10° to 40° C.

4. The method of claim 3 wherein the resin coating on the wooden article is dried for 5 to 30 minutes at a temperature of 15° to 30° C.

5. The method of claim 1 wherein the wooden article is a hockey stick blade.

6. The method of claim 1 wherein the wooden article is a golf club head.

7. The method of claim 1 wherein the wooden article is a baseball bat.

8. The method of claim 1 wherein the wooden article is a bowling pin.

9. The method of claim 1 wherein the prepolymerized resin is a phenoxy resin.

10. The method of claim 1 wherein the prepolymerized resin is a polyamide resin.

11. A wooden article having at least an impact area protected with a 0.1 to 0.5 mm thick coating of essentially a prepolymerized phenoxy resin of the formula wherein n = 150 to 700 and having a molecular weight of from 45,000 to 200,000 or prepolymerized polyamide resin having a molecular weight of 5,000 to 10,000 or mixtures thereof.

12. The wooden article according to claim 11 wherein said impact area is a hockey stick blade.

13. The wooden article according to claim 11 wherein said impact area is a golf club head.

14. The wooden article according to claim 11 wherein said impact area is a baseball bat head.

15. The wooden article according to claim 11 wherein said impact area is a bowling pin belly.