GB2064570A - Rubber scraper - Google Patents

Abstract

A rubber scraper, e.g. for cleaning roads, comprises a rubber composition prepared by heating and curing a mixture of (a) at least one rubber selected from diene rubbers and ethylene-propylene rubbers, (b) an alpha , beta -ethylenically unsaturated carboxylic acid, wherein the ratio by weight of the component (a) to the component (b) is from 83/17 to 65/35, (c) a divalent metal compound present in an amount of 50 to 110 parts by weight per 100 parts by weight of the component (b), and (d) an organic peroxide present in an amount of 0.3 to 4.5 parts by weight per 100 parts by weight of the sum of the components (a) and (b), and having a scraping surface perpendicular to an orientation direction of the rubber composition, the said orientation direction being produced by extrusion and/or sheeting.

Description

SPECIFICATION Rubber scraper This invention relates to a rubber scraper having improved scraping ability and durability.

The term "rubber scraper" as used herein means a rubber article used for scraping and removing deposits such as ice, snow and gravel from a surface of for example a road or belt conveyor.

In general, rubber scrapers of this type are required to have good scraping ability and durability. In order to achieve satisfactory scraping ability, the rubber scraper must have (1) a high bending modulus of elasticity (or high hardness) so as to prevent warping in use and (2) a high creep resistance so as to prevent flatting after use. Further, in order to achieve satisfactory durability, the rubber scraper must have (3) a high tear resistance and (4) a high abrasion resistance. For this purpose, the rubber scraper is usually required to have a stress per unit area at 50% elongation (Mod50) of not less that 30 kg/cm2, a creep quality (aye) of not more than 2.5%, a tear strength (T) of about 50 kg/cm and an abrasion resistance ensuring a running life of about 500 km.

Hitherto, there have been used carbon black reinforced rubber scrapers and urethane rubber scrapers. However, it has been confirmed that all of these scrapers do not fully satisfy the abovementioned requirements.

The present inventors have already proposed that rubber compositions which are obtained by heating and curing a mixture of a diene rubber, an a,-ethylenically unsaturated carboxylic acid, a divalent metal compound and an organic peroxide or an admixture of this mixture with a secondary aryl amine have an excellent fatigue resistance (Japanese Patent Laid Open Nos. 85,842/78 and 57,553/79). However, scrapers manufactured from these rubber compositions still do not have the properties mentioned above.

The inventors have made various studies with respect to the development of rubber scrapers satisfying the above-mentioned requirements, and as a result it has been found that a rubber scraper having improved scraping ability and durability can be obtained by utilizing a composition range having a certain orientation anisotropy and by extruding or sheeting such a composition so as to further improve the orientation anisotropy and shaping, heating and curing it so as to have a scraping surface perpendicular to the orientation direction.

The present invention provides a rubber scraper comprising a rubber composition prepared by heating and curing a mixture of (a) at least one rubber selected from diene rubbers and ethylenepropylene rubbers, (b) an a"ss-ethylenically unsaturated carboxylic acid, wherein the ratio by weight of the component (a) to the component (b) is from 83/17 to 65/35, (c) a divalent metal compound present in an amount of 50 to 110 parts by weight per 100 parts by weight of the component (b), and (d) an organic peroxide present in an amount of 0.3 to 4.5 parts by weight per 100 parts by weight of the sum of the components (a) and (b), and having a scraping surface perpendicular to an orientation direction of the rubber composition, the said orientation direction being produced by extrusion and/or sheeting.

The rubber composition of the scraper according to the invention may suitably further comprise (e) a secondary aryl amine present in an amount of 0.1 to 3.0 parts by weight per 100 parts by weight of the sum of the components (a) and (b).

The component (a) to be used in the invention is at least one rubber selected from diene rubbers and ethylene-propylene rubbers. Suitable diene rubbers include natural rubber, homopolymers of conjugated dienes such as 1,3-butadiene, isoprene and chloroprene, and copolymers of the conjugated dienes with acrylonitrile or alkenyl aromatic hydrocarbon compounds such as styrene. Among these, 1,3-butadiene homopolymers (i.e. butadiene rubber, hereinafter abbreviated as BR), butadiene-styrene copolymers (styrene butadiene rubber, hereinafter abbreviated as SBR) and natural rubber (hereinafter abbreviated as NR) are preferably used. In these diene rubbers, the cis-1,4 configuration is preferably not less than 30% by weight.

Suitable ethylene-propylene rubbers to be used as the component (a) include ethylene-propylene copolymers and ethylene-propylene-diene terpolymers. A terpolymer is preferably used.

As the component (a), a diene rubber or an ethylene-propylene rubber may be used alone or in admixture thereof and may further contain an appropriate amount of a non-diene rubber such as an isoprene-isobutylene copolymer.

The cr"B-ethyíenically unsaturated carboxylic acid to be used as the component (b) may suitably comprise methacrylic acid (hereinafter abbreviated as MAA), acrylic acid or ethacrylic acid, of which methacrylic acid is preferred. The weight ratio of the component (a) to the component (b) should be in the range of 83/1 7 to 65/35. When the amount of the component (b) is less than 1 7% by weight, the function of the scraping surface perpendicular to the orientation direction of the rubber composition or the orientation anisotropy does not sufficiently enhance the bending modulus of elasticity for prevention of warping, the creep resistance for prevention of flatting, and the tear strength resistance to chipping, while the abrasion resistance is poor.Further, when the amount of the component (b) exceeds 35% by weight, the orientation anisotropy to the above properties becomes conspicuous, while the abrasion resistance is considerably lowered.

The divaient metal compound to be used as the component (c) may be suitably an oxide, hydroxide or carbonate of zinc, magnesium or calcium. Of these, zinc oxide, especially activated zinc oxide, is preferred. The component (c) should be employed in an amount sufficient to neutralize all the carboxyl groups in the component (b). The amount of the component (c) may be varied according to the kind of the component (b) the kind of metal or the form of metal compound, but usually comprises 50 to 110 parts by weight per 100 parts by weight of the component (b). When the component (c) is compounded in too large an amount, the elongatioin at break decreases and chipping is apt to be caused.

The organic peroxide to be used as the component (d) may be suitably a dialkyl peroxide such as dicumyl peroxide (hereinafter abbreviated as DCPO), 1,1 -bis (t-butylperoxy)-3,3,5-trimethyl cyciohexane (hereinafter abbreviated as P-3 M), di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxy hexane, or a,a'-bis-t-butylperoxy-p-diisopropylbenzene. Among these DCPO and P-3M are preferred.

The component (d) is employed in an amount of 0.3 to 4.5 parts by weight per 100 parts by weight of the sum of the components (a) and (b). When the amount of the component (d) is less than 0.3 part by weight, the modulus of elasticity of the rubber composition is too low, while when the amount thereof exceeds 4.5 parts by weight, the modulus of elasticity becomes too high and chipping is apt to be caused.

By using a rubber composition composed of the above components (a)-(d), a rubber scraper having a highly satisfactory performance can be manufactured. Moreover, in order to improve the flatness during curing and also the internal uniformity in order to overcome problems arising from differences in properties between the surface part and the internal part of a thick moulded product, the component (e) may be added.

The secondary aryl amine to be used as the component (e) may be suitably N-isopropyl-Nt-phenyl- p-phenylenediamine, phenyl-a-naphthylamine, phenyl-P-naphthylamine, N,N'-di-2-naphthyl-pphenylenediamine, diphenyl-p-phenylenediamine, p-isopropyl diphenylamine, p-(p-toluenesulfonamido)-diphenylamine, or diphenylamine. Among these, N-isopropyl-N'-phenyl-pphenylenediamine (hereinafter abbreviated as 81 ONA) is preferred. The component (e) is employed in an amount of 0.1 to 3.0 parts by weight per 100 parts by weight of the sum of the components (a) and (b). When the amount of the component (e) is less than 0.1 part by weight, the addition effect is very small, while when the amount thereof is more than 3.0 parts by weight, the hardness of the resulting rubber composition is considerably reduced.

If it is intended to impart thermal resistance to the rubber scraper according to the invention, a reaction product of an amine and a ketone such as a 1 ,2-dihydro-2,2,4-trimethyl quinoline polymer (hereinafter abbreviated as RD) may be added to the rubber composition. In this case, the practical addition amount of the reaction product is 0.1 to 3.0 parts by weight per 100 parts by weight of the sum of the components (a) and (b).

Furthermore, the rubber composition of the scraper according to the invention may have incorporated therein a filler such as carbon black or silica, which is used in ordinary rubber compoundings.

Moreover, in order to improve the fatigue resistance of the rubber composition, there may be added thereto a carboxylic acid which may be a saturated fatty acid such as stearic acid, an unsaturated fatty acid such as oleic acid, an alicyclic carboxylic acid such as naphthenic acid, an aryl carboxylic acid such as benzoic acid, or a metal salt thereof. The metal of such a metal salt may be suitably zinc, calcium or magnesium.

The hardness of a rubber having the above-mentioned composition in accordance with the invention is 800 to 980 Shore A hardness. When the hardness is less than 800, warping of the resulting scraper is caused in use with consequent reduction of the scraping ability, while when the hardness exceeds 980, the resulting scraper becomes more brittle and hence chipping is frequently caused which degrades the abrasion resistance.

In a rubber scraper according to the invention, the scraping surface is perpendicular to an orientation direction of the rubber composition suitably produced by a sheet extrusion machine such as a rolling machine, a calendering machine, or an extruding machine. That is, the mixture of the abovementioned components is formed into a sheet-like rubber composition by a sheet extrusion machine, during which an orientation direction is given to the rubber composition. In general, it is known that when an ordinary rubber composition is formed by a sheet extrusion machine of the above type, orientation hardly occurs. Therefore, it is surprising that the rubber composition of a scraper according to the invention possesses an orientation direction.

The rubber composition thus oriented is heated and cured to manufacture a rubber scraper having a plane perpendicular to the orientation direction of the rubber composition as a scraping surface. In this case, the curing of the rubber composition is usually carried out at 11 110-1 800 C. When the curing temperature is lower than 1 1 OOC, a long curing time is required, while when the curing temperature is higher than 1 800 C, the resulting rubber scraper becomes more brittle.

The invention will be further described with reference to the following iilustrative Examples. In the Examples reference will be made to the accompanying drawings, wherein: Figures 1 a and 1 b are schematic perspective views of rubber scrapers having an orientation direction shown by arrows, respectively, wherein Figure 1 a shows a rubber scraper according to the present invention having a scraping surface perpendicular to the orientation direction (hereinafter referred to as an a-type scraper), and Figure 1 b shows a conventionally used rubber scraper having a scraping surface parallel to the orientation direction (hereinafter referred to as a p-type scraper); Figure 2 is a perspective view of an oriented rubber scraper sheet having various specimens cut therefrom;; Figure 3 is a schematic perspective view of an apparatus for measuring the abrasion loss of a rubber scraper; Figures 4 and 5 are graphs showing the relation between the weight ratio of the components (b)/(a) and abrasion loss, respectively; and Figure 6 is a graph showing the relation between abrasion loss and severity.

EXAMPLE 1 This example shows that the rubber composition of a scraper according to the invention having a compounding recipe shown in the following Table 1 has an orientation anisotropy, compared to a conventional rubber composition having the same compounding recipe.

TABLE 1

Component Compounding recipe (a) BR BFVMAA = 77/23 (b) MAA (c) ZnO 1 ZnO/MAA = 95/100 (d) DCPO DCPO/BR+MAA = 0.77/100 Curing conditions 150tC x 30 min.

The rubber composition having the above compounding recipe was extruded through an extruder so as to impart an orientation direction to the composition and then cured under the above curing conditions to prepare two specimens. Next, the linear expansion coefficient (k) was measured with respect to the two specimens. As a result, the linear expansion coefficient of a specimen measured at a direction parallel to the orientation direction was k=1 .72 xl 0-5 deg-l, while that of another specimen measured at a direction perpendicular to the orientation direction was k=4.72 x 1 O-4deg-'.

EXAMPLE 2 In this example, the orientation experiment was made by changing the weight ratio of the components (b)/(a).

In a kneader were thoroughly and uniformly mixed given quantities (as shown in the following Table 2) of BR containing 98% of cis-1,4 configuration (made by Japan Synthetic Rubber Co. Ltd., trade name BRO1) and NR as the component (a) (weight ratio of BR/NR is constantly 70/30), activated zinc oxide (hereinafter abbreviated as ZnO) as the component (c), 81 ONA as the component (e) and further other additives of RD, stearic acid (hereinafter abbreviated as St-acid) and carbon black HAF-LS. The resulting mixture was added and blended with a given quantity of MAA as the component (b) several times.To this blended mass was added a given quantity of P-3M as the component (d) by means of rolls, and then the resulting mixture was oriented in the usual manner to obtain an oriented unvulcanized sheet with a thickness of 2 mm. Next, this sheet was heated and cured in a slab mold at 1 500C for 30 minutes to form an oriented vulcanized sheet.

Two specimens A and B of JIS No. 3 dumbbell shape as shown in Fig. 2 were cut out from the above vulcanized sheet, respectively. The stress per unit area at 50% elongation (Mod50) of each specimen was measured using an Instron tester at a pulling rate of 200 mm/min to obtain results as shown in Table 2.

TABLE 2

Run No. 1a 1b 1c 1d 1e (b)/(a) MAA/BR+NR 0/100 9/91 13/87 17/83 23/77 (c)/(b) ZnO/MAA 75/100 75/100 75/100 75/100 75/100 Compounding recipe (d)/(a) + (b) P-3M/BR + NR + MAA 2.6/100 2.4/100 2.3/100 2.2/100 2.0/100 (e)/(a) + (b) 810NA/BR + NR + MAA 1.2/100 1.1/100 1.0/100 1.0/100 0.9/100 Mod50A 8.54 16.7 23.5 30.0 62.4 Mod50(kg/cm2) Mod50A 8.47 15.9 21.0 26.6 38.0 Mod50A/Mod50B 1.01 1.05 1.07 1.13 1.64 Note: 1.As other additives, RD, St-acid and HAF-LS were added in quantities of 1.2, 3 and 20 parts by weight per 100 parts by weight of the component (a), respectively.

2. In Run Nos. 1a-1e, the quantities of the components (d) and (e) were somewhat changed, but this change did not affect the orientation anisotropy.

From the results of Table 2, it is apparent that a ratio of Mod50 of the specimen A (i.e. Mod50A in a direction parallel to the orientation direction) to Mod50 of the specimen B (i.e. Mod:0 in a direction perpendicular to the orientation direction) increases as the weight ratio of the components (b)/(a) increases. In particular, the orientation anisotropy becomes conspicuous as the weight ratio of the components (b)/(a) exceeds 17/83.

The rubber scraper is required to have a high bending modulus of elasticity for preventing warping of the scraper in use. Considering that the bending modulus of elasticity is roughly proportional to Mod50, that Mod50A is larger than Mod:0 shows that the a-type scraper is very advantageous for the prevention of warping.

EXAMPLE 3 From the same vulcanized sheet as described in Example 2 were cut out two strip specimens C and D with a size of 5x 1 00x2 mm as shown in Figure 2. The creep quantity of each specimen was measured at room temperature under a load of 10 kg/cm2 by means of a creep tester to obtain a result as shown in the following Table 3.

TABLE 3

Run No. 2b 2c 2d 2e (b)/(a) MAA/BR+NR 9/91 13/87 17/83 23/77 ##C 4.73 2.98 2.16 1.76 ## (%) ##D 5.38 3.20 2.95 2.91 ##C/##D 0.88 0.93 0.73 0.60 From the results of Table 3, it is apparent that the ratio of AE of the specimen C (i.e. ##C in a direction parallel to the orientation direction) to AE of the specimen D (i.e. AED in a direction perpendicular to the orientation direction) rapidly decreases as the weight ratio of the components (b)/(a) exceeds 17/83 and hence the orientation anisotropy becomes conspicuous.

The creep resistance is estimated by the creep quantity (AE=E24-E1), which is obtained by subtracting the creep quantity after 1 hour (E,), from the creep quantity after 24 hours (E24) and is relevant to the flatting phenomenon of the rubber scraper after use. Since the smaller the value of the creep quantity, the more the prevention of the flatting, it can be seen that the a-type scraper is advantageous for the prevention of flatting.

EXAMPLE 4 From the same vulcanized sheet as described in Example 2 were cut out two parallel sided strip specimens E and F with a size of 10x100x2 mm as shown in Fig. 2. In each specimen, a notch of 2 mm was formed at the center of one edge. The strength at break ( b) of each specimen was measured using an Instron tester at a pulling rate of 200 mm/min, from which the tear strength (T) was calculated according to the following equation: T=#b/d wherein d is the thickness of the specimen (i.e. 2 mm). The measured results are shown in the following Table 4.

TABLE 4

Run No. 3b 3c 3d 3e (b)/(a) MAA/BR+NR 9/91 13/87 17183 23/77 TE 46.1 43.7 77.9 122 T (kg/cm) TF 43.6 40.5 36.7 37.6 TE/TF 1.06 1.08 2.12 3.24 From the results of Table 4, it is apparent that the ratio of the tear strength TE of the specimen E (measured in a direction parallel to the orientation direction) to the tear strength TF of the specimen F (measured in a direction perpendicular to the orientation direction) increases with the increase of the weight ratio of the components (b)/(a), and in particular the increase of the ratio TE/TF becomes conspicuous as the weight ratio of the components (b)/(a) exceeds 1 7/83.

The tear strength is relevant to the resistance against chipping, i.e. the higher the tear strength, the larger the resistance against chipping. Therefore, that TE is higher than TF shows that the cr-type scraper has a large resistance against chipping as compared with the p-type scraper.

EXAMPLE 5 A mixture having a compounding recipe shown in the following Table 5 was blended and oriented in the same manner as described in Example 2 to prepare two simulated rubber scrapers corresponding to the a- and -type scrapers of Figure 2 (a size of 30x55x60 mm, a scraping surface of 30x60 mm).

An abrasion test on these two scrapers was made under conditions similar to actual running conditions using an apparatus for measurement of abrasion loss shown in Figure 3 as follows. First, a rubber scraper 7 was secured to a fixing member 5, which was connected to the rear body 1 of an electric car through a coupling member 2 and a movable pin 3, with fitting screws 6 in such a manner that the scraping surface of the rubber scraper 7 was inclined at an angle of 30 to the ground and a load of 0.17 kg/cm2 was applied thereto by putting an adjustable weight 4 on the fixing member 5. Then, the electric car was run on a concrete paved road at a speed of 2 km/hr over a distance of 0.1 6 km in the direction indicated by the arrow 8.Thereafter, the abrasion loss (AV) of the rubber scraper 7 was measured in terms of abraded thickness when the scraping surface was run for a distance of 1 km to obtain a result as shown in Table 5 and Figures 4 and 5.

TABLE 5

Run No. 4a 4b 4c 4d 4e (b)/(a) MAA/BR+NR 13/87 17/83 23/77 29/71 33/67 (c)/(b) ZnO/MAA 75/100 75/100 75/100 75/100 75/100 Compounding recipe (d)/(a) + (b) DCPO/BR+NR+MAA 5.6/100 4.3/100 1.7/100 0.7/100 0.3/100 (c)/(a) + (b) 810NA/BR+NR+MAA 0.6/100 0.6/100 0.5/100 0.5/100 0.5/100 Hd ( ,Shore A hardness) 95 95 95 95.5 95 #Vα 1.84 0.683 0.139 0.228 0.478 #V (mm/km) #Vss 1.88 0.683 0.156 0.333 0.750 #Vα/#Vss 0.98 1.00 0.88 0.69 0.54 Note: 1. As other additives, RD, St-acid and HAF-LS were added in quantities of 0.7, 3 and 20 parts by weight per 100 parts by weight of the component (a), respectively.

2. The weight ratio of BR/NR was constantly 70/30.

3. In order to make the hardness constant, the quantity of the component (d) was changed.

In Table 5, AVa is the abrasion loss of the a-type scraper and AVp is the abrasion loss of the type scraper. From the results of Table 5 and Fig. 4, it is apparent that the ratio of the abrasion loss AVa/AVP decreases with the increase of the weight ratio of the components (b)/(a), and in particular the orientation anisotropy to the abrasion resistance becomes conspicuous as the weight ratio of the components (b)/(a) exceeds 17/83. This shows that the a-type scraper has a superior abrasion resistance to the type scraper.

Moreover, it can be seen from Fig. 5 showing the relation between the weight ratio of the components (b)/(a) and the abrasion loss AVa of the a-type scraper that the abrasion resistance considerably deteriorates when the weight ratio (b)/(a) is smaller than 17/83 or exceeds 35/65. From this it is apparent that the weight ratio of the components (b)/(a) should be limited to a range of 1 7/83 to 35/65. In Fig. 5, the level of abrasion resistance shown by broken lines corresponds to a level capable of developing a durability of about 500 km in practically used products.

EXAMPLE 6 A rubber composition having a compounding recipe as shown in the following Table 6 was used to prepare two a- and type simulated rubber scrapers in the same manner as described in Example 5.

Then, the abrasion test was made with respect to the two scrapers under the same conditions as described in Example 5 to obtain a result as shown in the following Table 7.

TABLE 6

Component Compounding recipe (a) BR, + NR MAA/BR+NR = 25/52.5+22.5 (b) MAA (c) ZnO ZnO/MAA = 75/100 (d) DCPO DCPO/BR+NR+MAA = 0.72/100 Curing conditions: 1650C x 30 min.

Note: As other additives, St-acid and HAF-LS were added in quantities of 3 and 20 parts by weight per 100 parts by weight of the component (a), respectively.

TABLE 7

α-type scraper ss-type scraper Hd ( , Shore A hardness) 97 97 Abrasion loss #V (mm/km) #Vα = 0.169 #Vss = 0.235 As apparent from the results of Table 7, the ratio of abrasion loss AV /AVP is 0.72, so that the atype scraper has a superior abrasion resistance to the p-type scraper.

EXAMPLE 7 A rubber composition having a compounding recipe as shown in the following Table 8, which develops a remarkable orientation anisotropy to the abrasion resistance, was used to prepare two aand ,3-type simulated rubber scrapers in the same manner as described in Example 5. For comparison, there was provided a rubber scraper made from a typical polyurethane as shown in Table 8.

TABLE 8

Run No. 8a 8b 8c (a) BR+NR MAA/BR+NR Polyurethane =28.6/50.0+21.4 produced by (b) MAA reacting poly propylene glycol (c) ZnO ZnO/MAA=100/100 with tolylene diisocyanate in DCPO/BR+NR+MAA (d) DCPO the presence of =1.14/100 Compounding 4,4'-methylene recipe (e) 810NA @@@0NA/BR+NR+MAA bis-2-chloroaniline =0.93/100 As other additives, RD, St-acid and HAF-LS were added in quantities of 1.3, 3 and 20 parts by weight per 100 parts by weight of the com ponent (a), respectively.

α-type ss-type Curing conditions 160'C x 30 min.

Hd (@, Shore A hardness 94 96 The abrasion test was made with respect to these three scrapers in the same manner as described in Example 5, except that the severity of the abrasion conditions was changed by varying the value of the adjustable weight 4 in the apparatus shown in Figure 3, to obtain a result as shown in Figure 6.

In Figure 6, symbol # represents the result of the polyurethane rubber scraper, symbol O the result of the ss-type scraper, and symbol # the result of the α-type scraper. On the abscissa of Figure 6 is plotted the abrasion loss of the polyurethane rubber scraper as the severity, while the ordinate represents the abrasion loss of each of the a- and -Wpe scrapers measured under the same severity condition.

From the results of Figure 6, it is apparent that the abrasion resistance is improved in the order of the polyurethane rubber scraper < the type scraper < the a-type scraper. Furthermore, it is apparent that the relative abrasion loss of these scrapers depends upon the severity.

EXAMPLE 8 Show plough blades with a size of 30 mm (thickness) x 200 mm (width) x 810 mm (length) were manufactured by using the same polyurethane rubber scraper and a-type scraper as described in Example 7. Then, the abrasion resistance and snow-scraping performance of each snow plough blade were measured on the Tohoku expressway under actual snowfalling conditions to obtain a result as shown in the following Table 9.

TABLE 9

Polyurethane a-type scraper rubber scraper Running distance (km) 288 405 Abrasion loss (mm) 14.3 42.7 Abrasion loss per unit distance (mm/km) 5.0 x 102 1.05 x 10-@ Snow-scraping no fusion Fusion and chipping performance not chipping occurred due to heat generation From the results of Table 9, it is apparent that the abrasion loss per unit distance of the a-type scraper is about a half of that of the polyurethane rubber scraper, which completely corresponds to the measured result of Example 6. That is, the result of Example 7 shows that the laboratory result of Example 6 is reproduced in the practical test of Example 7. From this it is shown that the a-type scraper has a superior abrasion resistance to the p-type scraper even in the practical test. Further, the snowscraping performance of the a-type scraper is superior to that of the polyurethane rubber scraper. Thus it can be said that the a-type scraper according to the invention performs satisfactorily as a rubber scraper as compared with the conventional rubber scraper.

Claims (3)

1. A rubber scraper comprising a rubber composition prepared by heating and curing a mixture of (a) at least one rubber selected from diene rubbers and ethylene-propylene rubbers, (b) an ethylenically unsaturated carboxylic acid, wherein the ratio by weight of the component (a) to the component (b) is from 83/17 to 65/35, (c) a divalent metal compound present in an amount of 50 to 110 parts by weight per 100 parts by weight of the component (b), and (d) an organic peroxide present in an amount of 0.3 to 4.5 parts by weight per 100 parts by weight of the sum of the components (a) and (b), and having a scraping surface perpendicular to an orientation direction of the rubber composition, the said orientation direction being produced by extrusion and/or sheeting.

2. A rubber scraper as claimed in claim 1, wherein the rubber composition further comprise (e) a secondary aryl amine present in an amount of 0.1 to 3.0 parts by weight per 100 parts by weight of the sum of the components (a) and (b).

3. A rubber scraper according to claim 1, substantially as herein described in Table 1, run 1 d or 1 e of Table 2, run 4b, 4c, 4d or 4e of Table 5, Table 6, or run 8a or 8b of Table 8.