US3466778A

US3466778A - Signs

Info

Publication number: US3466778A
Application number: US429385A
Authority: US
Inventors: William R Varnell; Mance R Mitchell
Original assignee: Concrete Development Corp
Current assignee: Concrete Development Corp
Priority date: 1965-02-01
Filing date: 1965-02-01
Publication date: 1969-09-16
Anticipated expiration: 1986-09-16

Description

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sept. 16, 1969 United States Patent O 3,466,778 SIGNS William R. Varnell and Mance R. Mitchell, San Antonio, Tex., assignors to Concrete Development Corporation, San Antonio, Tex., a corporation of Texas Filed Feb. 1, 1965` Ser. No. 429,385 Int. Cl. G09f 7/16, 7/00 U.S. Cl. 40--136 2 Claims ABSTRACT OF THE DISCLOSURE An integrally formed concrete sign and sign context is made from polyester concrete by mixing polyester resin with aggregate in the amount of about 40% to about 95% aggregate of the total mixture by weight. The mixture is placed in a mold to form a body having a major plane with a plurality of laterally spaced openings extending entirely through the body in a direction transverse to the major plane of the body, and the mixture is allowed to cure.

This invention relates to signs made with polyester resin and methods for making such signs.

The manufacture of conventional signs, particularly those used outdoors, is an expensive process requiring the selection of a suitable substum material upon which the sign is superimposed by painting, photographic techniques, and a variety of other expensive processes. Outdoor signs presently in use are usually made of wood or metal, and must be treated to prevent weathering, plus the subsequent conventional sign painting processes with coating materials which generally have inferior weathering characteristics. Such signs are not only expensive to manufacture, but they are expensive to maintain.

This invention overcomes the disadvantages of conventional signs by the use of polyester resin. In one form, a sign includes a body having a message surface with sign characteristics on the message surface of the body. A coating of polyester resin is disposed over the sign, body, and characters to protect them from weathering.

In one specific embodiment, the message surface of the sign body is covered with a rst coating of polyester resin which may be colored by conventional pigment materials to provide a desired background color. The sign characters are painted or formed on the message surface of the body using polyester resin which carries pigment of a contrasting color. The polyester resin not only provides a permanent sign background and sign characters, but it also protects the sign body from weathering. Since polyester resin is virtually immune to weathering attack, the sign body and the message on it have an almost indelinite life.

In another form of the invention, the sign body is coated with polyester resin, and lsign characters formed of polyester resin cement concrete are bonded to the surface of the sign with polyester resin cement. The terms polyester resin, polyester resin cement, and polyester resin cement concrete are defined below.

In the presently preferred embodiment of the invention, the sign is made of a body having a message Surface and cast from polyester concrete which includes graded agice gregate present in the amount of about 40% to about 95% of the product by weight. The particle size of the aggregate ranges from less than 400 mesh up through a size limited to about one-half the thickness of the concrete, and usually from about one-eighth inch to about threeeighths inch sieve size. The use of the carefully graded aggregate provides a lightweight polyester resin concrete of unusually high strength, plus the additional advantage of inertness to weathering. Signs made of this material weigh substantially less than those made from metal, and have the same physical characteristics such as tensile and comprehensive strength. A sign made from polyester concrete costs about 40% less than one made of metal and weighs about 50% less.

In one form, background color is dispersed throughout the message surface of the body, and sign characters are applied to the message surface either in the form of polyester concrete characters of a color contrasting with that of the background color, or polyester cement characters applied with a coating which carries pigment of a color contrasting with that in the message surface of the sign body. In either arrangement, the entire sign is polyester resin cement, or concrete, and is inert to weathering.

Preferably, the aggregate includes fines selected from the group consisting of titanium dioxide and silica flour in the amount of about 1% to about 50% of the product 'by weight. These lines are virtually free of any metal content, and therefore improve the shelf or pot life of the polyester resin cement or concrete. The fine aggregate also improves the strength of the final product, as well as enhancing its bonding characteristics.

In terms of method, the invention includes the steps of casting a body with a message surface from polyester concrete, allowing the mixture to set, and bonding sign characters onto the surface of the message body with polyester cement.

In one method of the invention, the sign characters are placed face down in the bottom of a mold for the sign. The polyester concrete mixture is poured into the mold and onto the characters and allowed to set so that the characters are bonded to the set concrete. The strength of the sign is further increased by applying pressure to the mixture of polyester concrete in the mold until the mixture has set.

These and other aspects of the invention will be more fully understood from the following detailed description and the accompanying drawings, in which:

FIG. 1 is an elevation in cross section of a polyester concrete sign being cast in a mold with the sign characters integral with the sign body;

FIG. 2 is an elevation of a polyester concrete sign having holes through it to reduce its weight and wind-loading;

FIG. 3 is a view taken on line 3 3 of FIG. 2;

FIG. 4 is an elevation in cross section of a pressure mold forming a polyester concrete sign with the sign characters being cast directly into the sign body;

FIG. 5 is an elevation of a sign made of conventional substrate and coated with polyester cement, sign characters in the form of polyester cement coating being applied to the coating on the substrate; and

FIG. 6 is a View taken on line 6 6 of FIG. 5.

The term polyester resin is used to mean a mixture of an ethylenically unsaturated alkyd resin and polymerizable vinyl monomer such as styrene. The preferred resins of this class for employment in the concrete compositions of the invention are the polymeric ester reaction products of one or more dicarboxylic acids and one or more polyhydric alcohols. One or more of these reactants contain a reactive double bond or ethylenic linkage. Among the dicarboxylic acids which may be used are phthalic, malic, maleic, fumaric, adipic, pimelic, suberic, sebacic, itaconic, citraconic, and succinic acids and their anhydrides. It is preferred that some of the dicarboxylic acid component of the polyester resin contain an unsaturated ethylenic linkage. For this reason, maleic and fumarie acids are most desirable. Among the polyhydric alcohols which may be used are ethylene glycol, diethylene glycol and propylene glycol. A mixture of propylene glycol and dipropylene glycol is a satisfactory polyhydric alcohol. An unsaturated monohydric alcohol may be used in place of part of the polyhydric alcohol. A typical example of such an alcohol is allyl alcohol which produces an allyl ester of the dicarboxylic acid. The polyester resins may be suitably modified or plasticized by the incorporation of alcohols, fatty acids, etc., to modify the chemical and physical characteristics as desired. The polyesters should comprise upward from about or 30% and preferably 40% to 85% by weight of the resin and resin forming component, c g., styrene, of the coating composition.

The resin should also contain a non-Volatile, monomeric, .cross-linking solvent for the polyester. The function of this solvent is to make the polyester resin more iluid and also to cross-link the polyester at the time of curing to produce a cross-linked, or three dimensional resin with the polyester which is thermosetting in character. This monomeric solvent is an important member of the resin component, for it provides the necessary fluidity to the resin component, imparts thermosetting characteristics to the cured resin and is consumed during the curing of the resin without forming volatile materials. This freedom from volatility is important, for otherwise the release of volatile matter would produce bubbles, voids, or pinholes on the surface and throughout the finished body of the product. The lack of volatile matter permits curing when under pressure without requiring provision for vents, etc., in the molds.

Among the monomeric polymerizable solvents which may be used are styrene, vinyl toluene, e.g., o-vinyl toluene, p-vinyl toluene, and m-vinyl toluene, cyclo-pentadiene; vinyl acetate; diallyl esters, e.g., diallyl phthalate and triallyl cyanurate, as well as alphamethyl styrene. Styrene has produced the most satisfactory results thus far.

When produced commercially, these resin compositions contain a small amount of a polymerization inhibitor so as to prevent gelation during storage prior to usage. Such inhibitors include the well known antioxidants: hydroquinone, t-butyl .catechoL quinone, etc.

Some of the polyester resins of the character contemplated for use in the present invention are sold in the trade and identified as Oronite, Polylite, Selectron, ParapleX, or Vibrin resins. In general, these resins are unsaturated high molecular weight polymers made by reacting one or more acids or a blend of acids, such as maleic or fumaric acid, with a dihydroxy alcohol, such as ethylene glycol. The speciiic properties of these resins vary depending largely upon the type and amount of each constituent in the combination.

As the catalysts, there can be utilized numerous oxidizing catalysts, such as cumene hydroperoxide, dicumyl peroxide, benzolyl peroxide, and methyl-ethyl-ketone peroxide. The catalyst is usually employed in an amount of 0.5-4% of the polyester resin. Preferably, there is utilized with the catalyst a metallic dryer such as manganese or cobalt naphthenate, for example. A typical example of a satisfactory catalyst-dryer combination is 2% benzolyl peroxide, .75% manganese naphthenate, and .75 cobalt naphthenate based on the polyester resin.

4 The term polyester cement is used to mean a mixture of polyester resin and between 1% and 50% agggregate having a particle size of less than 400 mesh. A typical polyester cement composition is given below:

Example 1 A polyester resin slurry was prepared by stirring in a mixing vessel a mixture having the following composition:

Percent y Weight About 60% by Weight of Oronite CR 21728 polyester resin (made by reacting 3 mols of isophathalic anhydride with 6 mols of diethylene glycol and 1. 5 mols of ethylene glycol, until the acid number is less than 5. Four mols of maleic anhydride is then added with ppm. hydroquinone and reacted until the acid number is below 20), and about 40% by weight of styrene monomer 69. 20

(The amount of styrene can be increased to about 60% by weight without adverse eiect on the nal product. The

Oronite CR 21728 is a so-called semilexible high impact resistance resin. Similar properties are obtained by blending an orthophathlic rigid resin with an orthophthalic flexible resin in a ratio of about 3.0 to 3.9 by Weight.)

(Preferably the silica flour has the chemical and screen analysis given in Table I below.)

Titanium dioxide Styrene The above materials are thoroughly mixed, and the mixture is referred to as polyester resin cement mix No. 1. It has a density of 10.5 pounds per gallon.

The above mixture has yan almost indefinite shelf life because of the presence of the finely divided and pure silica flour. It can be used as a primer or seal coat in patching conventional portland cement structures, or it can be mixed with aggregate and cast -as concrete.

Polyester resin cement mix No. 1 is used as the cementing agent of a concrete designed to meet strength specifications for polyester concrete signs. For example, a polyester concrete is made by mixing the following ingredients:

Example 2 Pounds Polyster resin cement mix No. 1 9.10 Methyl-ethyl-ketone peroxide 0.13

(This is preferably blended with the polyester resin Formula No. 1 prior to mixing with the larger aggregate.)

Additional silica our 15.17 Fine (No. 4 to No. 100) silica aggregate1 34.10 Medium 0%. to No. 4) silica aggregate1 41.50

The aggregate and polyester resin cement mix No. 1 are mixed in a standard concrete mixer for two or three minutes to disperse the various particle sizes uniformly throughout the entire mixture and to insure uniform coating of all -aggregate particles with polyester resin.

The above concrete mixture was then cast and cured to make a polyester concrete having a compressive strength of 10,000 p.s.i., and a tensile strength of 2,500 p.s.i. The above concrete may be cured at ambient temperature. If delay between mixing and placing polyester resin concrete is expected, the initial set may be delayed from 15 to 30 minutes to from 6 to 8 hours by introducing a conventional retarder, such as hydroquinone, in the polyester resin Formula No. 1 when the catalyst is added.

1(G rade in accordance with New York Port Authority gradation of aggregate schedule, see Table 1I below.)

The composition of the preferred silica flour is shown in Table I below:

The aggregate used in addition to the silica flour can be any material which does not adversely affect the curing of the polyester resin. Excellent results are obtained by using silica aggregate graded in accordance with the New York Port Authority Schedule shown in the following table:

TABLE II Percent passing by weight Fine Coarse 1% Coarse Sieve Size (square openings) aggregate aggregate aggregate 1 Used for thin sections. 2 Used for heavy sections.

The polyester resin concrete of Example 2 is satisfactory for use at temperatures up to about 80 C. (176 F.)

To make a polyester concrete for use at temperatures up to 130 C. (266 F.), Oronite CR 20114 polyester resin is substituted for Oronite CR 21728 in Examples 1 and 2. Other chemical and physical properties described above are not `materially changed. Oronite CR 20114 is an isophthalic unsaturated polyester made by reacting one mol of isophthalic anhydride with 3.41 ymols of propylene glycol at 400 F. until the acid number is below 5. Two mols of maleic anhydride are -added to the mixture, which is then cooked at 390 F. until the acid number is below 25. The temperature is then raised to 415 F. until the acid number is below 15. 150 p.p.m. of hydroquinone is added with the maleic anhydride.

Referring to FIG. 1, a body of polyester concrete is cast in a mold 11 to form a sign having a message surface 12 adjacent the bottom of the mold which is recessed at 13 to form sign characters 14 of polyester concrete cast integrally with the sign body on its message surface. The sign characters project away from the message surface so that they may be distinguished even though they are the same material as the body of the sign. However, preferably the sign characters carry reflective material, such as glass bea'ds, or an inert pigment of distinctive color which causes the sign characters to be more easily distinguished from the sign body. In one form, the recesses in the molds in which the sign characters are formed yare filled with glass beads or pigment of distinctive color. The polyester resin concrete is then poured into the mold Without disturbing the glass beads or pigment. After the concrete has set, the sign is removed from the mold with the message surface being appropriately covered With the desired message.

Alternatively, the recesses 13 in the mold are filled with glass beads or pigment with a distinctive color and then with polyester concrete. The floor or bottom of the mold is then covered with pigment of a contrasting color, and then the remainder of the polyester concrete is poured in place and allowed to set. The nal product is a sign with a message surface of one background color carrying sign characters of contrasting colors or appearance. The iinished product is light weight, yet strong and inert to weathering.

The sign shown in FIGS. 2 and 3 includes a relatively flat rectangular body 16 made of polyester concrete. The body includes a continuous border or periphery 1S which encloses a grid type of background made up of a plurality of intersecting diagonal strips 20 upon which polyester concrete Vsign characters 22 are bonded with polyester cement. Holes 23 between adjacent strips extend through the major plane of the sign body. Reinforcing rods 24 of aluminum, steel, or other suitable material may be employed, or chopped glass rovings approximately one-half inch in length may be incorporated into the polyester concrete mixture in an amount not exceeding 60% by weight of the resin content of the polyester concrete mixture. An aluminum reinforcing or post-tensioning band 26 is disposed around the periphery of the sign body and held in tension by a clamp 28 to provide additional strength to the sign. The open grid type of background of the sign shown in FIGS. 2 and 3 reduces the weight of the sign, its cost, and also allows air to pass through the structure and thereby decrease wind-loading requirements. This saving is further enhanced because the sign standard or support for the sign can be designed for reduced windloading.

Referring to FIG. 4, sign characters 30 are set face down in the bottom of a mold 32 and covered with polyester concrete 34 which is placed under pressure by a piston 36 to a pressure of 1500 to 3000 pounds per square inch. The polyester concrete sets in a strong dense body with the sign characters embedded in its message surface. After the concrete is set, the sign is removed from the mold and is ready for installation. If desired, the message surface of the sign is coated with a clear layer of polyester resin or cement to protect the sign characters if they are of material subject to weathering. Of course, this is not necessary if the sign characters are made of polyester concrete because a iilm of polyester resin cement covers the aggregate, beads, or pigment which form the sign characters.

Referring to FIGS. 5 and 6, a conventional sign substrate 40 is covered with a coating 41 of polyester resin cement, such as that given in Example 3 below. Sign characters 42 which may be conventional, or which are made of polyester concrete are bonded with polyester resin cement to the message surface 43 of the sign substrate. If the sign characters are of polyester concrete, they need uo further protection. If they are of a conventional material subject to weathering, they preferably are covered with a coating having the composition given in Example 3 below. The polyester coatings can be applied generally with conventional methods and equipment. Their application does not differ appreciably from applying conventional coatings and paints. However, there is one important advantage of the polyester coatings. They donot usually require prime coats, thus avoiding the multi-coat applications normally required in conventional coating systems. Thus, labor costs are reduced materially when polyester coatings are used because they can be applied in any desired thickness in a one-coat application.

A good polyester resin cement coating for protecting signs in accordance with this invention is given in the following example:

Example 3 A polyester resin cement coating com-position was prepared by stirring in a mixing vessel a mixture having the following composition:

EXAMPLE 3 Percent Y weight Oronite CR 19583 in about the amount ol' (Made by reacting 1 mol of isophthalic acid and 2.1 mols of propylene glycol until the acid number is less than 5, at which point 1 mol of maleic anhydride is added and the reaction continued until the acid number iS below 15, after which about 40% by weight oi styrene monomer is added. The desired acid number is between 10 and 15. The amount of styrene can be increased to about 60% by weight without adverse effect on the final product.)

Hydroquinone (approximately 150 p.p.m.) Wax (paran in nature, having a melting poin 125 F. and about 135 F.) Cobalt naphthenate Aluminum silicate (Al2SO3) Titanium dioxide (TiOZ) Silica dioxide (SiO 2) (Preferable the silica flour has the chemical and screen analysis given in Table I above.)

Styrene (alpha) 10.50

The above mixture was combined with 1.5 fluid ounces of methyl-ethyl-ketone peroxide per gallon of coating composition, and 14 grams or 12 cc. hydroquinone.

The pot life of the above mixture was determined and found to be about 6 to 8 hours at 80 F. This mixture was applied to a plain steel surface, after Sandblasting to commercial blast-clean specification by spray method at approximately to 25 mils lm thickness. The mixture was cured into a tough corrosion-resistant, semiflexible film within about 24 hours at 80 F. The coating of this formulation is particularly suitable in acid environment. The heat distortion point of the resin mixture is about 80 C Signs using polyester resin cement or concrete in accordance with this invention have many desirable characteristics not obtained with conventional signs. The polyester coatings cure to form a tough corrosion-resistant, abrasiveresistant film which has superior weathering characteristics because it provides an almost perfect moisture vapor barrier. The signs using polyester concrete are lightweight, have high strength, and are virtually inert to weather.

We claim:

1. A method for making an integrally formed concrete sign background and sign context from a polyester concrete comprising mixing polyester resin with an aggregate in the amount of about 40% to about 95% of the total mixture by Weight, the aggregate being graded in particle size and ranging from less than 400 mesh up through a size commonly limited to about 1/2 the thickness of the concrete being cast and usually to about 1A; inch to 3A; inch sieve size, placing preformed sign context characters on the face of a mold for the product,

placing the sign background mixture into the mold and on the characters to form a body having a major plane, forming a plurality of laterally spaced openings extending entirely through the body in a direction transverse to the major plane of the body, and allowing the polyester mixture to set or cure.

2. A method for making an integrally formed concrete sign background and sign context from a polyester concrete comprising mixing of polyester resin with an aggregate, in the amount of about 40% to about 95 of the total mixture by weight, the aggregate being graded in particle size and ranging from less than 400 mesh up through a size commonly limited to about 1/2 the thickness of the concrete being cast and usually to about 1A; inch to 3A; inch sieve size, placing preformed sign context characters on the face of a mold for the product, placing the sign background mixture into the mold and on the characters to form a body having a major plane, forming a plurality of laterally spaced openings extending entirely through the body in a direction transverse to the major plane of the body, applying pressure to the mixture in the mold, and allowing the polyester mixture to set or cure.

References Cited UNITED STATES PATENTS 1,953,784 4/1934 Straussner et al. 40-136 2,298,364 10/1942 Gits et al 40-136 2,354,857 8/1944 Gits et al 40-l36 2,863,241 12/1958 Gits 40-136 2,994,925 8/ 1961 Gits 40-136 LAWRENCE CHARLES, Primary Examiner