US2933989A

US2933989A - Traffic markers

Info

Publication number: US2933989A
Application number: US548865A
Authority: US
Inventors: D Adrian Vincent L Duval
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-11-25
Filing date: 1955-11-25
Publication date: 1960-04-26
Anticipated expiration: 1977-04-26

Description

April 26, 1960 v. 1.. DUVAL D'ADRIAN 2,933,989

TRAFFIC MARKERS Filed Nov. 25, 1955 CELLULOSE ETHYL ETHE R I00 90 8O 7O 6O 5O 4O 3O 20 IO 0 CASTOR WAX B ROSIN INVENTOR VINCENT L. DUVAL D'ADRIAN ATTORNEY TRAFFIC MARKERS Vincent L. Duval dAdrian, Shrewshnry, Mo.

Application November 25, 1955, Serial No. 548,865

7 Ciaims. (Ci. 94-15) This invention relates to improvements in traflic markers. More particularly this invention relates to improve ments in traffic marking compositions and in methods of installing such compositions.

It is therefore an object of the present invention to provide an improved trafiic marking composition and an irnproved method of installing such composition.

In guiding and directing trafiic, both vehicular and pedestrian, it is helpful to have markings directly on the areas on which the traflic moves. These areas are frequently surfaced with concrete or asphalt; and the markings are usually applied directly to such surfaces. Those markings are of two general types: one, a fluid that is painted on, or otherwise applied to, the trafiicbearing areas and then permited to harden; and two, solids in the form of tile that are secured to the trafficbearing areas by asphalt coatings. One aspect of the present invention is to provide a traffic marking composition that can be applied to traflic-bearing areas in either the fluid state or the solid state. It is therefore an object of the present invention to provide a trafiic marking composition that can be applied to traflic-bearing areas in either the fluid state or the solid state.

The fact that the traffic marking composition of the said one aspect of the present invention can be applied to trafiic-bearing areas while it is in the fluid state is important since it is frequently important to designate trafiic lanes by continuous strips or lines, and such strips or lines are most easily formed by trafiic marking compositions in the fluid state. Paint is a traflic marking composition in the fluid state, and it is widely used. However, the trafiic marking composition of the said one aspect of the present invention will be more viscous than paint, and it can therefore form a thicker, and longer-lived, traffic marking than paint can form. This is very desirable because it assures the benefits of traffic marking for longer periods of time.

Many different kinds of traflic tile have been proposed, and some of them have ben used. Those tiles are customarily made from a plastic material; and they are usually secured to the traffic-bearing areas by coatings of asphalt. Those tiles are usually serviceable on smooth flat areas as long as the asphalt coatings hold them in place. Unfortunately, however, the coatings of asphalt are frequently incapable of resisting the dislodging forces applied to the tile by vehicles. This, of course, is objectionable. The said one aspect of the present invention obviates this objection by providing a traflic tile that inherently possesses the ability to adhere to trafficbearing areas. Such a tile does not require a coating of asphalt; and hence it is not subject to displacement due to failure of that coating of asphalt. It is therefore an object of the present invention to provide a traflic tile that inherently possesses the ability to adhere to trafficbearing areas.

The composition used in making the traflic tile of the said one aspect of the present invention can be rendered fluid and then applied to traflic-bearing areas while in 2,933,989 Patented Aprr 26, 1960 fig W the fluid state. That composition will thereafter change from the fluid state to the solid state; and it will inher' ently adhere to the traffic-bearing area when it becomes solid.

The traffic marking composition provided by the said one aspect of the present invention includes a normally non-tacky rosin material that responds to heat to become tacky and adhesive in nature. When the trafiic marking composition of the said one aspect of the present inven= tion is heated, the normally non-tacky material becomes tacky and adhesive in nature and renders the said trafiic marking composition tacky and adhesive. As a result, that composition will adhere to a traflic-bearing area to which it is applied. It is therefore an object of the said one aspect of the present invention to provide a traflic marking composition which includes a normally non-tacky rosin material that becomes tacky in nature when it is heated.

The traffic marking composition provided by the present invention is heat softenable; and hence it can be softened, by the application of heat, to the point where it will conform to irregularities in the surfaces of the traffic-bearing areas. The resultant intimate contact between the traflic marking composition and the trafiicbearing areas is of the greatest importance because it eliminates any need of that composition bridging low spots in the surfaces of the trafiic-bearing areas. 'The traflic marking composition is thus freed from the stresses and strains which a bridging action would entail. It is therefore an object of the present invention to provide a traflic marking composition which is heat softenable and which can be softened sufiiciently, by the application of heat, to conform to variations in the surfaces of the trafic-bearing areas.

The traflic marking composition provided by the said one aspect of the present invention is a solid at ambient temperatures; and while it softens during the heating step used in installing that composition, it hardens almost immediately thereafter. Consequently, this traflic marking composition does not require the long hardening or drying period that paints require; and hence traflic interruptions are minimal during installation of this traflic marking composition. In addition, the fact that this traific marking composition does not require a coating of asphalt also reduces the time required to install it.

To be commercially successful, a traflic marking composition must be strongly resistant to wear in summer and Winter, and it must be resistant to the blows imparted to it by the skid chains used on vehicles in the winter. The present invention provides a traffic marking composition that is tough while being yieldable. It is therefore an object of the present invention to provide a traflic marking composition that is tough while being yieldable.

It is frequently desirable to make trafiic markings light reflective. Some painted traffic markings have been made light reflective by sprinkling glass beads onto them as they were drying; and those beads were very helpful as long as they were held by the paint. All too frequently, however, those beads were dislodged by the rapidly accelerating or rapidly decelerating tires of vehicles. Further, since the beads were wholly at the upper surfaces of the painted traffic markings, those beads were the very first portions of those markings to be worn away. Consequently, even when a good part of a painted marking remains, the beads may be gone. This is objectionable. The present invention obviates that objection by distributing light reflective beads throughout all portions of a traflic marking composition. The upper surface of such a composition can wear away without reducing the light reflective capability of that composition, because the resulting upper surface will be impregnated with addi- 2,983,989 V V r tional reflective beads. It is therefore an object of the present invention to provide a trafiic marking composition throughout which light reflective beads are uniformly distributed.

It is of the greatest importance that the light reflective beads be tightly held in traffic marking compositions. If those beads become separated from the traffic marking compositions, those compositions will lose some of their light reflectivity; and further, dirt and road soil can lodge in the sockets previously occupied by the beads. The present invention provides a traffic marking composition that has light reflective beads and that tightly holds those beads. V Trafiic marking compositions that have lightrefiective beads distributed uniformly throughout the'm' tendto lose their light reflectivity because of dirt, discoloration and road soil; the beads tending to grip and hold the dirt and road soil on the tires of vehicles. The present invention obviates the loss of light reflectivity by providing a traflic marking composition that tends to shed dirt, discoloration and road soil. That trafiic marking composition strongly resists the application of dirt, discoloration and road soil to it, and it also quickly sheds any dirt, discoloration and road soil that may actually be applied to it. It is therefore an object of the preesnt invention to provide a trafiic marking composition that sheds dirt, discoloration and road soil.

The traffic marking composition provided by the present invention is enabled to shed dirt, discoloration and road soil because it has a waxy phase distributed uniformly throughout it. That waxy phase is, in part at least, separated from the other phase of the traffic marking composition provided by the present invention; and it provides a waxy feel for that composition. It is therefore an object of the present invention to provide a traffic marking composition which has a waxy phase that gives it a waxy feel.

The traffic marking composition provided by the present invention can be colored by distributing pigment uniformly throughout it. The color of that traffic marking composition will be fully effective at all times because the waxy phase of that composition will keep dirt, discoloration and road soil from obscuring or aberrating that color. Hence, the trailic marking composition provided by the present invention has an unusually high degree of a color quality.

Other and further objects andv advantages of the pres ent invention should become apparent from an examination of the drawing and accompanying description.

"In the drawing and accompanying description several preferred embodiments of the present invention are shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that the invention will be defined by the appended claims. The drawing is a trilinear chart showing the proportions of one preferred ternary composition usable in making the traffic marking composition of the present invention.

The traffic marking composition of the present invention is a form-retaining substantially Water-insoluble, relatively inelastic formulation that is resistant to flow at ambient temperatures, that has a low degree of inflammability, that is not brittle, that has a high degree of retention .for glass beads, that has a waxy feel, and that is heat softenable. In addition, that traffic marking composition may be formulated so it becomes tacky and adhesive in nature when it is heated. That composition will preferably be used as a vehicle for pigment, light Eelilective beads, abrasion resistant filler and reinforcing The waxy feel of the trafiic marking composition is dominantly due to the presence of a waxy material. The form-retention, the relative inelasticity, the resistance to 4 l flow, and the high retention for glass beads are domi' nantly due to the presence of a strength-giving material. The waxy material can be a single substance or it can be a mixture of two or more substances; and similarly, the strength-giving material can be a single substance or it can be a mixture of two or more substances. If the trafiic marking composition is to be formulated so it is tacky and adhesive in nature when heated, the strengthgiving material will usually be a mixture of two or more substances; one of those substances being'a toughening material, and the other of those substances being a heat softenable binding material.

A number of different toughening materials can be 7 used in preparing the trathc marking composition of the present invention. The following materials are believed to be representative of the toughening materials that can be used: cellulose ethyl ethers, cellulose propyl ethers, ethyl hydroxyethyl cellulose mixed ethers, polyvinyl butyrals, and vinyl acetate polymers. Each of these materials is resistant to flow at ambient temperatures, is not dark in color, is substantially water-insoluble, has a low degree of infiammability, is relatively inelastic, has a high molecular weight, and can be rendered compatible with a waxy material. While the above-identified list of toughening materials is representative, it is not exhaustive; and other high molecular weight toughening materials having similar properties can be used. For example, higher alkyl celluloses such as cellulose butyl ethers and cellulose amyl ethers should be usable, but they are not yet commercially available. From the point of view of cost and availability, the cellulose ethyl esters are the most attractive of these toughening materials.

A number of difierent waxy materials can be used in preparing the trafiic marking composition of the present invention. The following materials are believed to be representative of the waxy materials that can be used: hydrogenated castor oil, which is referred to commercially as castor wax, glycol distearate, glycol dipalmitate. polyethylene, oxidized polyethylene, carnauba wax, bees wax, candelilla Wax, palmitic acid and stearic acid. Each of these materials is substantially water-insoluble, is not dark in color, has a low degree of inflammability, is a solid at room temperature, and can be rendered compatible with a strength-giving materiaL- The compatibility of these waxy materials with strength-giving materials must not be permanent where the resulting composition is to be exposed to traflic; instead, the waxy material must separate out in part as a waxy phase. This separation of the waxy material is important since is enables that material to provide a waxy feel for the traiiic marking composition which enables that composition to shed dirt, discoloration and road soil. While the above-identified list of waxy materials is representative, it is not exhaustive.

It is desirable that the waxy phase remain in the solid state after the trafiic marking composition has been applied to the traflic-bearing area. This means that the waxy material must have a melting point that is high enough to enable the waxy phase to remain solid even though it is exposed to the direct rays of the summer sun. Some of the above-listed waxy materials have melting temperatures that are high enough to permit their use in traffic marking compositions intended for the torrid zone, other of the above-listed waxy materials have melting points that are not high enough to permit their use in trafiic marking compositions intended for the torrid zone but are high enough for use in traffic marking compositions intended for the temperate zones, and still other of the waxy materials have such low melting points that they are best used in traffic marking compositions intended for the frigid zones. For example, castor wax having a melting temperature of about eight-six (86) degrees centigrade, carnauba wax having a melting tem perature of about eight-five degrees centigrade, glycol distearate having a melting temperature of about seventy-seven (77) degrees centigrade, ca'ndelilla Wax having a melting temperature of about seventy-five (75) degrees centigrade, and polyethylene and oxidized polyethylene having a softening temperature of about one hundred (100) degrees centigrade are well adapted for use in trafiic marking compositions intended for the torrid zone. Castor wax having a melting temperature of about seventy (70) degrees centigrade, glycol dipalmitate having a melting range of about seventy (70) degrees Centigrade, stearic acid having a melting range of about sixty-nine (69) degrees centigrade, and palmitic acid h v ing a melting range of about sixty-four (64) degrees Centigrade are adapted for use in traffic marking compositions intended for the temperate zone. Castor wax having a melting temperature of about sixty (60) degrees Centigrade, and bees Wax having a melting temperature of about sixty-one (61) degrees centigrade are best adapted for use in trafiic marking compositions intended for the frigid Zone. It is possible to use most of the higher melting temperature waxy materials in traffic marking compositions intended for the temperate zones and the frigid zones as well as in traffic marking compositions intended for the torrid zone; and similarly it is possible to use most of the intermediate melting temperature waxy materials in traffic marking compositions intended for the frigid zones as well as in trafiic marking compositions intended for the temperate zones. However, the low melting temperature waxy materials should be used only in tratlic marking compositions intended for cool climates.

A number of different heat softenable binding materials can be used in preparing the trailic marking composition of the present invention. The following materials are believed to be representative of the heat softenable binding materials that can be used: rosin, including wood rosin and gum rosin; modified rosin, including heat modified rosins, polymerized rosins, ester gums, hydrogenated resins and hydrogenated rosin esters, maleic modified rosin esters, and epoxy modified rosin esters; natural rosin gums such as dammar gum and copal; and ph nolformaldehyde resins of the oil-soluble non-heat hardeni, type. While the above-identified list of heat softena'ole binding materials is representative, it is not exhaustive. Any one of these heat softenable binding materials can be formulated with a toughening material and a waxy material; and if desired, mixtures of two or more of these heat softenable binding materials can be formulated with a toughening material and a waxy material. Further, if desired, some of these materials can be mixed with heat softenable plastic materials that have been plasticized to have properties similar to rosin; and then the resultant mixture can be formulated with a toughening material and a waxy material. For example, a phenolformaldehyde resin of the oil-soluble non-heat hardening type can be mixed with polystyrene that has been plasticized with a chlorinated biphenyl; and thereafter the resulting mixture can be formulated with a waxy material and a toughening material.

Each of the heat softenable binding materials listed above is substantially water-insoluble, is available in grades that are not dark in color, has a low degree of iniiarnmability, is resistant to fiow at ambient emperatures, becomes tacky and adhesive in nature in the presence of heat, and is compatible with organic toughening materials. tom the point of view of cost, availability and general application, wood resin is the most attractive of the heat softenable binding materials.

in formulating the trafl lc marking composition provided by the present invention, the amount of Waxy material that is used must exceed the amount of waxy material that can be dissolved or dispersed in that composition. Such an arrangement makes certain that a waxy phase will separate out and provide the essential dirt-shedding characteristic for the trafiic mark ng composition. The extent to which the waxy material can be A wide range of traflic marking compositions is contemplated by the present invention; and those compositions fall into two groups. One group possesses the property of inherently adhering to traffic-bearing areas while the second group does not possess that property. The various toughening materials referred to herein can be used in the tralfic marking compositions of both groups. Similarly, the various waxy materials referred to herein can be used in the trafiic marking compositions of both groups. The heat softenable binding material will not, however, be used, if at all, to an appreciable degree in the traffic marking compositions of the second It is not practical to list all of the usable traflic marking compositions contemplated by the present invention. Instead, only a small representative number of traffic marking compositions is being described in detail.

Each of the trafiic marking compositions described herein will preferably have light reflective beads, pigment and fillers added to them. InExample I the COu. plete formulation, including light reflective beads, ment and fillers, is given; but in the rest of the examples, for the sake of brevity, only the percentages of the toughening material, the waxy material and the heat softenable binding material are given. Those percentages are, in all instances, based on weight rather than volume.

Example I One trafilc marking composition of the one group that has been found to be extremely useful and serviceable consists of sixty (60) pounds of wood rosin, thirty-six (36) pounds of castor wax having a melting temperature of about eighty-six (86) degrees centigrade, sixteen (16) pounds of cellulose ethyl ether having an ethoxyl content of approximately forty nine percent (49%) and a viscosity number of one hundred and fifty (150) c.p.s., one hundred pounds of seventy to one hundred (70-100) mesh glass beads, fifty (59) pounds of Ashes tine, thirty (30) pounds of one hundred (100) mesh mica, and twenty (20) pounds of titanium dioxide. In formulating this traffic marking composition, the Wood resin is obtained in the form of chips or lumps, usually through the breaking up of the contents of a barrel of rosin; and the castor wax is obtained in the form or flakes. The rosin and castor wax are heated to a temperature of about three hundred (300) degrees Fahrenheit; and that temperature is maintained for about one half /2) hour. The rosin and castor wax are stirred and mixed during that one half /2) hour with an agitator, as for example a commercial dough mixer; and at the end of the one half /2) hour period, the rosin and castor wax are liquefied. The beads are then added; and the addition of the beads causes the temperature of the liquefied rosin and castor wax to drop. The stirring and heating are continued until the temperature again reaches three hundred (300) degrees Fahrenheit; and this usually takes about fifteen (15) minutes. The beads are held in suspension by the stirring and agitating action of the agitator; and while the agitating and stirring action continues, the asbestine and mica are added. As these fillers are taken up by the liquid, the pigment is added. At this time the heads, the fillers, and the pigment are in suspension in the liquefied rosin and caster wax; and the mixture is at a temperature of about three hundred (389) degrees Fahrenheit. The temperature is thereupon raised to three hundred and fifty (350) degrees Fahrenheit; and the temperature is stabilized at that level. The cellulose ethyl ether is obtained in granular form, and it is passed through a forty (40) mesh screen as it is introduced into the mixture. That screen holds back any lumps and large particles that would have too large a volume-to-surface ratio to readily combine with the liquefied rosin and castor wax 'toform a compatible system. The mixture is maintained at the temperature of about three hundred and fifty (350) degrees Fahrenheit for about two (2) hours; and then the mixture is permitted to cool to ambienttemperature.

On cooling, the rosin, the castor wax and the cellulose ethyl ether do not remain permanently compatible; instead, a waxy phase separates out. That waxy phase appears to be, at least in part, in finely divided crystalline form.

Prior to the completion of the separation of the waxy phase, the traffic marking composition is slightly tacky; but upon the completion of that separation, the tramc marking composition is non-tacky. After the completion of the separation of the waxy phase, the tratfic marking composition is stifier than it was before that separation was complete. At the conclusion of the separation of the waxy phase, the traffic marking composition can be handled and packaged readily.

Where titanium dioxide is used as the pigment for the tratfic marking composition, that composition will be white. If the trafiic marking composition is to be colored, the percentage of titanium dioxide should be reduced, and a colored pigment should be substituted for the titanium dioxide that has been left out. For example, if the traffic marking composition is to be made yellow in color, sixteen (16) pounds of lead chromate can be substituted for sixteen (16) of the twenty (20) pounds of titanium dioxide.

The percentage of light reflective beads that are to be added, and the size of those beads, are not critical. However, it has been found that glass beads smaller than one hundred (100) mesh do not provide the high degree of reflectivity desired, and glass beads larger than seventy (70) mesh tend to retain and hold dirt, discoloration and road soil.

Asbestine is used in this formulation as a reinforcing and strengthening filler. However, other comparable fillers could be used.

Mica is used in this formulation as a wear-resistant and abrasion-resistant filler. However, other comparable fillers could be used.

The steps that are outlined above in the formulation of Example I of the traflic marking composition of the present invention can be carried out in different sequences, but the particular sequence outlined above is particular- 1y useful in facilitating the formulation of that traffic marking composition. Where, as in Example I, the traffic marking composition is to be used as a vehicle for pigment, light reflective beads and fillers, it is desirable to admix' the waxy material and the heat softenable binding material first. This is done in the presence of heat, and the resultant mixture liquefies rather readily. The pigment, light reflective beads and fillers can be dispersed throughout the resulting liquid with ease. Usually the light reflective beads will be added first, then the fillers will be added, and finally the pigment will be added. Once these ingredients have been added and thoroughly intermixed, the toughening agent can be added. The resulting composition is retained in the form of a rather viscous liquid until all of the ingredients are thoroughly intermixed; and thereafter the composition is cooled. If the trafiic marking composition is to be used as trafiic marking tile, the composition will be poured onto platens and pressed to the desired thickness. The desired dimensions and configurations for the individual tratfic tile can then be obtained by cutting the pressed-out trafiic marking composition; that cutting preferably being done while the pressed out composition is still warm. If desired, the trafiic marking composition of Example I can be extruded from an extrusion press; and the desired configuration for the traflic tile can be provided by the die of that press.

If the traffic marking composition is to be stored in fluid form, it will have a suitable solvent mixed with it.

For example, when the traffic marking compositionhas cooled to about seventy-five degrees centigrade, one (1) gallon of isopropyl alcohol can be added for each two and one half (2.5) pounds of composition. Thereafter, the resulting mixture is held at a temperature just below the boiling point of the alcohol while the mixture is stirred; and finally a paste-like consistency is attained.

If the traific marking composition of the present invention is to be used without light reflective beads, fillers or pigments. the above sequence of steps can be altered by deleting appropriate step or steps. Thus, if light reflective beads are not to be used, the fillers can be added after the waxy material and heat softenable binding material have been liquefied.

Care must be taken, during the formulation of Example 1 of the trafiic marking composition of the present invention, to keep the toughening material, the heat softenable binding material and the waxy material from forming a permanently compatible system. Similarly, care must be taken, during the formulation of any trar'iic marking composition employing castor wax, to keep the waxy material and the strength-giving material from becoming permanently compatible. This need for care arises from the fact that castor wax can be degraded, by pro longed heating at certain temperature levels, to the point where its melting point is decreased and its compatibility with the strength-giving material is increased.

If the waxy material and the strength-giving material were permitted to become permanently compatible, the resulting composition could not provide the waxy feel that is needed to shed dirt, discoloration and road soil. Further, such a permanently compatible system would be permanently tacky and adhesive and would collect, rather than shed, dirt, discoloration and road soil.

The need for care is particularly great because the temperatures used to liquefy the admixed strength-giving material and Waxy material are high enough to cause thermal degradation or" the castor wax. For example wood rosin, cellulose ethyl ether and castor Wax can be made into a permanently compatible system by holding them at a temperature of two hundred and fifty (250) degrees Fahrenheit for forty-eight (48) hours; and yet a temperature of three, hundred and fifty (350) degrees is a desirable temperature to use in forming the temporarily compatible system of the traffic marking composition of the present invention. By limiting the time during which the traffic marking compositions, containing castor wax, are held at elevated temperatures, those compositions can be kept from becoming permanently compatible.

in Example I, the mixture is held at a temperature (300) degrees Fahrenheit for less than an hour, and the mixture is then held at three hundred and fifty (350) degrees Fahrenheit for just over two hours. Such a heating schedule will render the rosin, the cellulose ethyl ether and the castor wax temporarily, rather than permanently, compatible.

If a batch of the trafiic marking composition has to be held overnight, it can be kept in a heated state without becoming permanently compatible by holding its temperature at about two hundred and ten (210) degrees Fahrenheit.

In the event a batch of traffic marking composition ever becomes permanently compatible, it can be made temporarily compatible by changing its composition. For example, a permanently compatible, and thus unusable, batch of resin, cellulose ethyl ether and castor wax can be rendered temporarily compatible, and thus useful, by adding a small amount of polyethylene.

The determination of whether a composition of a strength-giving material and a waxy material is temporarily or is permanently compatible is easily made. The permanently compatible mixture is a substantially clear liquid when hot and remains substantially clear upon cooling and hardening; while a temporarily compatible mixture is a substantially clear liquid when hot and becomes cloudy upon cooling and hardening.

A good part of the waxy material should separate out of the temporarily compatible system when that system cools, thereby providing a waxy phase. However, the toughening material and the heat softenable binding material, where the strength-giving material includes both, should not separate out appreciably, if at all. Instead, those latter materials, and a part of the waxy material should remain in mutually dispersed condition. Consequently, the toughening material and the binding material must have a high compatibility for each other when cool as well as when hot; while the waxy material must have a high compatibility for the binding material and the toughening material when hot but must have a lower degree of compatibility for those materials when cool.

if desired, the toughening material, the waxy material and the heat softenable binding material of Example I could be used directly as a traflic marking composition. Preferably, however, it will be used as a vehicle. It could, for example be used as a vehicle for pigment and a filler such as sand. It could also be used as a vehicle for pigment, sand and asbestine. However, that traflic marking composition will preferably be used as a vehicle for light reflective beads, pigment and fillers. The nature and quantity of light reflective beads, pigment and fillers is not critical. The critical factor in the traffic marking composition of the present invention is the temporarily compatible system of strength-giving material and an excess of waxy material. That system must be solid and tough at ambient temperatures, must be capable of being softened by the application of heat, and must have a waxy feel to shed dirt, discoloration and road soil. in addition, that system should be able to hold beads, fillers and pigment against dislodgement by the tires of vehicles.

Example I] Another traffic marking composition of the one group consists of fifty (50) parts of hydrogenated rosin ester, thirty (30) parts of glycol distearate, and twenty (20) parts of cellulose ethyl ether. The hydrogenated rosin ester and the glycol distearate are admixed and heated until they melt. Thereafter the temperature is raised to about three hundred and fifty (350) degrees Fahrenheit and the cellulose ethyl ether is added. The resulting mixture becomes compatible in about two (2) hours, depending upon the rate at which it is agitated and stirred and depending upon the total weight of the batch. The hydrogenated rosin ester used in this example is Staybelite resin 742.

The resulting tramc marking composition can, as indicated above, be used directly for traific marking or can be used as a vehicle for light reflective beads, pigment and filler. Preferably it will be used as a vehicle for beads, pigment and filler.

Example III Another trailic marking composition of the one group consists of fifty-four (54) parts of wood rosin, thirtytwo (32) parts of candelilla wax, and fourteen (14) parts of polyvinyl butyral resin. The polyvinyl butyral resin used herein is resin XYSG. The wood rosin and the candelilla wax are admixed and heated until they melt. Thereafter the temperature is raised to about three hundred and sixty-five (365) degrees Fahrenheit and the polyvinyl butyral resin is added. The resulting mixture becomes compatible in about one and one half (1 /2) hours, depending upon the rate at which it is agitated and stirred and depending upon the total weight of the batch.

This particular traflic marking composition has a high degree of retentivity for light reflective beads. Further, it has a high degree of inherent adherency for traflicbearing areas.

10 Example I V Still another trafiic marking composition of the one group consists of thirty-seven (37) parts of Wood rosin, twenty-seven (27) parts of oil-soluble phenol formaldehyde resin, thirty-two (32) parts of castor wax having a melting temperature of about eighty-six (86) degrees centigrade, and fourteen (14) parts of polyvinyl butyral. The oil-soluble phenol formaldehyde resin is resin Br. 10282. The polyvinyl butyral is resin XYSG.

The wood rosin and the castor wax are admixed and heated until they melt. Thereafter the temperature is raised to about three hundred and fifty (350) degrees Fahrenheit, and the polyvinyl butyral is added. The resulting mixture becomes compatible in about one and three quarters (1%) hours, depending upon the rate at which it is agitated and stirred and depending upon the total weight of the batch. At this time the phenol formaldehyde resin is added, and the stirring and heating is continued until the mixture is homogeneous; this usually happening within one quarter A) of an hour.

This particular traffic mark ng composition has a high degree of rententivity for light reflective beads. Further, it has a high degree of inherent adherency for trafficbearing areas.

Example V An example of a traffic marking composition of the second type consists of sixty (60) parts of cellulose ethyl ether and forty (40) parts of castor wax having a melting temperature of about eighty-six (86) degrees centigrade. The cellulose ethyl other is of the low viscosity type (10 cps.) and has a forty-eight to forty-nine and one-half percent Mil-49.5%) ethoxyl content. The caster wax is heated until it melts; and thereafter the temperature is raised to about three hundred and seventy (370) degrees Fahrenheit, and the cellulose ethyl ether is added. The resulting mixture becomes compatible in about one and one quarter (1%.) hours, depending upon the rate at which it is agitated and stirred and depending upon the total weight of the batch.

This tralfic marking composition will not be inherently adherent to traffic-bearing areas; and hence a bonding material must be used to affix the tralfic marking composition to the tratfic-bearing area. However, this trafiic marking composition will have an adequate retentivity for light reflective beads.

Example V1 Another example of a traflic marking composition of the second type consists of seventy-five (75) parts of polyvinyl acetate and twenty-five (25) parts of polyethylene. The polyvinyl acetate is resin AYAT, and the polyethylene is a low molecular Weight grade.

The polyethylene is heated until it melts; and thereafter the temperature is raised to about three hundred and sixty-five (365) degrees Fahrenheit. The polyvinyl acetate is added; and the resulting mixture becomes uniformly dispersed within about one and three quarters (1% hours, depending upon the rate at which it is stirred and depending upon the total weight of the batch. The resultant dispersion is quite viscous; and it is tough and horn-like on cooling.

This particular trafiic marking composition has a very high retentivity for light reflective heads, but it does not have an inherent adherency for traflic-bearing areas. Accordingly, this trafiic marking composition must be aflixed to the traffic-bearing area by a bonding material.

The trafiic marking compositions of the one group can be applied to traffic-bearing areas in three different ways; the particular way being dependent upon the form which the trafiic marking composition is to have when it is applied to the traffic-bearing areas. Specifically, if the trafiic marking compositions of the one group are to be applied in the form of tile, those compositions can be aflixed to traffic-bearing areas by .reason of their inherent adherency or by a bonding material. If the traflic marking compositions of the one group are to be applied in the form of a continuous strip or line, those compositions can be applied to the traflic-bearing areas in fluid form and then heated to bond them to those areas. The traflic marking compositions of the second group must be applied to the trafic-bearing areas by a bonding material.

One bonding material that has been found to be very useful is a permanently compatible mixture of castor wax, a toughening material, and a heat softenable binding material. In particular a composition of about fifty-five (55) parts of wood rosin, thirty (30) parts of castor wax, and fifteen (15) parts of cellulose ethyl ether can be heated overnight at three hundred and fifty (350) degrees Fahrenheit to render it permanently compatible. The resulting composition is tacky and adherent to trafficbearing areas and to traflic marking tile of plastic material. This composition will preferably be rendered fluid by a solvent, as for example isopropyl alcohol. One very useful way of rendering the bonding composition fluid is to add the isopropyl alcohol to that composition as it is cooling down from the three hundred and fifty (350) degree Fahrenheit temperature. In doing so it will material is below the boiling point of the alcohol; otherwise a good part of the alcohol could be lost by evaporation.

The resulting fluid will have the form of a creamy suspension, and it can be stored and transported in fluid form. The bonding material can be applied with a brush or other suitable instrument; and the alcohol can then be evaporated. To remove the alcohol solvent of the bonding material, the flame of a blow torch can be played over the bonding material after it has been applied to the traflic-bearing area. The bonding material is then in condition to receive and tightly hold trafiic marking tile; and it will hold those tile whether or not those tile are made from traffic marking compositions of the one group or the second group.

It will be desirable to heat the bottom surfaces of the traflic marking tile, and to heat the bonding material, before the trafflc marking tile is pressed into engagement ,with the bonding material. The heat will drive off any moisture on the bottom surface of the traflic marking tile or on the top surface of the bonding material. Further, that heat will enhance the adherence between the trafiic marking tile and the bonding material.

The bonding material is not necessary where the trafiic marking tiles are inherently adherent; because those tiles can adhere to clean concrete, asphalt and the like. However, since it is not always easy or convenient to clean the surfaces of traffic-bearing areas, it will usually be desirable to apply a thin coating of the bonding mate- ,rial or of some dust-laying material. When used in this manner, the bonding material functions primarily as a dust-laying coating. -Such a dust-laying coating could be made from paint, lacquer, rubber cement, bituminous material or the like; the primary requisite of the dustlaying coating being that it provides a non-oily, dust-free surface. Such a coating is particularly useful where the traffic-bearing area is of concrete, because concrete tends to form a fine dust at its surface; and that dust could interfere with the adherence of the traffic marking tiles to the concrete.

The tralfic marking tiles of the present invention are heat softenable; and the flame of the blow torch will quickly soften the bottom surface of the tiles. Usually, a bottom surface of the traflic marking tile can be softened sufficiently in less than a minute. 'Ihereupon, the trafiie marking tile is pressed against the traffic-bearing area or the dust-laying coating thereon, as the case may be. The bottom surface of that tile hardens quickly and if that tile has been applied to a substantially fiat .traflicbearing area, the tile is then ready to bear trafiric.

be advisable to wait until the temperature of the bonding In the event the traffic-bearing area is not substantially smooth, the traflic marking tile should not be permitted to harden quickly. Instead, the flame of the blow torch should be applied to the upper surface of that traffic marking tile immediately after that tile has been pressed into engagement with the traffic-bearing area or with the dust-laying coating. That flame can soften that traffic marking tile to the point where that tile conforms fully to the surface of the traffic-bearing area.

During the flame-heating of the bottom of the traffic marking tile, that bottom softens and becomes sticky. The waxy material, of course, softens; but the component that both softens and becomes sticky is the dispersion of the binding material and the toughening material. That dispersion hardens upon cooling and intimately bonds the tratfic marking tile to the traflic-bearing area.

Where the traffic marking compositions of the one group are to be applied as a line or strip, the compositions can be rendered fluid in the manner described above. Those compositions can be applied to the traflic-beariug areas by extruding them onto those surfaces or by applying them to those areas and then spreading them to the desired width and thickness. Heat, usually provided by a flame, is then applied to the strip or line until the solvent is evaporated and the tralfic marking compositions are fused into masses of uniform texture which are free of bubbles. After cooling to ambient temperature the marking strip or line is ready to bear traflic.

The thickness of the resulting strip or line will be greater than the thickness of a painted line; and hence the strip or line of traflic marking composition will last a good deal longer than a painted strip or line. Further, the strip or line of a traffic marking composition can have light reflective beads distributed uniformly throughout it; and hence it can still be light reflective after its upper surface has, in time, worn away.

The strips or lines of traffic marking composition provided by the present invention will adhere tightly to the trafiic-bearing area. Furthermore, because they are applied in the form of a fluid, they will be able to follow any irregularities in the surfaces of the trafliic-bearing areas.

When the traflic marking compositions of the present invention are flame heated they tend to discolor. However, that discoloration disappears quite quickly, even when trafiic is permitted to move over those compositions immediately after they are applied to the traffic-bearing areas. The discoloration disappears more readily in warm weather, but in any event it usually disappears within a twenty-four (24) hour period.

Where the tops of the trafiic marking compositions are flame heated to cause those compositions to conform intimately to rough surface, those tops will be tacky for a short period of time. If the flow of trafiic is to be resumed almost immediately, it is advisable to sprinkle mica dust or glass beads onto those flame-heated tops. The beads or the mica dust form a temporary coating on the tops of the traflic marking compositions that keeps those compositions from accumulating excessive amounts of dirt, discoloration or road soil during the short, tacky period. 7

In the chart of the drawing, cellulose ethyl ether having a viscosity of one hundred and fifty cps. and an ethoxyl content of from forty-eight to forty-nine and one half percent (4 849.5%) is represented by coordinate A; castor wax having a melting temperature of about eighty-six (86) degrees centigrade is represented by coordinate B; and wood rosin is represented by coordinate C. 'These coordinates are demarked according to the percentages, by weight, which the cellulose ethyl ether, the castor wax and the wood rosin bear to the overall composition of the three. The quadrilateral polygon defined by the vertices W. X, Y and Z on the chart of the drawing includes a number of points representing .raflic marking compositions formed from various percentages ace-2,989

of cellulose ethyl ether, wood resin and castor wax. These traflic marking compositions are particularly desirable because they are relatively inexpensive, they are composed of readily available materials, and they are inherently adherent to traific-bearing areas. Vertex W is located at A10, B70 and C20; vertex X is located at A5, B15 and C80; vertex Y is located at A10, B10 and C80; and vertex Z is located at A58, B22 and C20. The trafiic marking compositions represented by points within the polygon W, X, Y and Z possess the properties and characteristics of trafic marking compositions of the one group; those trafiic marking compositions being resistant to impact and to wear, being inherently adherent, and having a waxy feel. Traffic marking compositions, on the polygon W, X, Y and Z, having less than five percent by weight of cellulose ethyl ether tend to be unable to withstand satisfactorily the heavy impact of tires of vehicles and of the skid chains of vehicles during cold weather; and trafiic marking compositions having more than sixty percent (60%) by weight of cellulose ethyl ether tend to have less than the required compatibility of the cellulose ethyl ether and the wood rosin. Traffic marking compositions, on the polygon W, X, Y and Z, having less than twenty percent (20%) by weight of wood rosin tend to fail to have enough inherent adherency to adhere satisfactorily to the traffic-bearing surfaces; and traific marking compositions having more than eighty percent (80%) by weight of wood, rosin tend to be too brittle and to be insufiiciently resistant to wear and abrasion. Trafiic marking compositions, on the polygon W, X, Y and Z, having less than ten percent castor wax by Weight do not satisfactorily shed dirt and discoloration in all kinds of weather; and trafiic marking compositions having more than seventy percent (70%) by weight tend to be insufficiently adherent to the trafficbearing areas or tend to be insuflicienfly tough and wearresistant.

Trafiic marking compositions of the second group are represented by points within the quadrilateral polygon defined by the vertices U, V, W and X on the chart of the drawing. Other traffic marking compositions of the second group are represented by points on the line UV on the chart of the drawing. The vertex U is located at A75, B25 and C0, and the vertex V is located at A20, B80 and C0. The trafiic marking compositions represented by points within the polygon U, V, W, and X, and by points on the line UV, will have a waxy feel and will have impact resistance and wear resistance and will also have a high retentivity for light reflective heads, but they will not have any inherent adherency that will enable them to be applied to concrete without a bonding mate rial. However the bonding material described above will hold those traffic marking compositions to concrete in a permanent and intimate manner.

Cellulose ethyl ether having a viscosity of one hundred and fifty (150) cps. and an ethoxyl content of fortyeight to forty-nine and one half percent (48-49.5%) is the preferred toughening material, but it is possible to substitute for it any of the commercially available cellulose ethyl ethers having viscosities above seven (7) cps. and ethoxyl contents above forty-four and one half percent (44.5%). Further, it is possible to substitute any of the various toughening materials listed above.

Wood rosin is the preferred binding material but it is possible to substitute gum rosin or any of the various heat softenable binding agents listed above. Gum rosin, like wood rosin, is an inexpensive and readily obtainable heat softenable binding material; but the substitution of gum rosin for Wood rosin makes the resulting traffic marking composition harder when it is in the solid state. Further, traflic marking compositions using gum rosin instead of 'wood rosin require much more closely controlled temperatures during the mixing operations. Unless the temperatures are controlled more closely than when wood rosin is used, the traflic markers embodying gum rosin tend to have insufiiicent adhesion to the tratlic-bearing areas. Moreover, traflic marking compositions with gum rosin usually require higher temperatures than do the compositions with wood rosin; and those higher temperatures tend to darken the gum rosin. Consequently more pigment is required with trafi'ic markers made with gum rosin.

Whereas .he drawing and accompanying description have described several preferred embodiments of the present invention, it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

1. A form-retaining, heat softenable, traffic marking composition substantially non-tacky at ambient temperature containing as the essential ingredients thereof a compatible phase and a separated waxy phase, said compatible phase consisting essentially of a substantially water-insoluble, toughening material of the group consisting of cellulose alkyl ethers and alkyl hydroxyalkyl cellulose mixed ethers; a heat-softenable binding material of the group consisting of wood rosin, gum rosin, heat modified rosin, polymerized rosin, ester gum, hydrogenated rosin, hydrogenated rosin esters, maleic modified rosin esters and epoxy modified rosin esters; and castor wax, said castor wax constituting part of said compatible phase and constituting said separated waxy phase, said ingredients being distributed uniformly throughout said traffic marking composition, said compatible phase consisting essentially of about 558% of said toughening material, about 20-80% of said binding material, and part of said castor wax, the total amount of castor wax in said compatible phase and in said separated waxy phase being about 30-70% of the total weight of said compatible phase plus said separated waxy phase.

2. A composition according to claim 1 including light reflective beads uniformly distributed through it.

3. A composition according to claim 1 including a pigment.

4. A composition according to claim 2 including a pigment.

5. A composition according to claim 1 containing 55% by weight of wood rosin, 30% by weight of castor Wax and 15% of cellulose ethyl ether.

6. A composition according to claim 1 containing 60% by weight of cellulose ethyl ether and 40% by weight of castor wax.

7. A process for marking a trafiic bearing area comprising heating a composition defined in claim 1, applying said heated composition to a traffic bearing area, and permitting said traffic marking composition to cool whereby said composition becomes bonded to said trafiic hearing area.

References Cited in the file of this patent UNITED STATES PATENTS 1,729,834 Jackson Oct. 1, 1929 1,925,921 Godfrey Sept. 5, 1933 2,186,454 Gloor Jan. 9, 1940 2,268,538 Rodli et al. Dec. 30, 1941 2,297,709 Kauppi et al. Oct. 6, 1942 2,311,609 Kauppi et al. Feb. 16, 1943 2,354,049 Palmquist July 18, 1944 2,379,702 Gebhard July 3, 1945 2,393,525 Farrell Jan. 22, 1946 2,413,011 Traylor et al. Dec. 24, 1946 2,574,971 Heltzer Nov. 13, 1951 2,694,027 Calkins Nov. 9, 1954