AnimateMaterial.cs

using UnityEngine;
using System.Collections;

public class AnimateMaterial : MonoBehaviour {

  public float scrollSpeedU = 0.0f;
  public float scrollSpeedV = 0.25f;
  
  public float amplitudeU = 0.0f;
  public float amplitudeV = 0.0f;
  
  void Update() {
    float offsetU = 0.0f;
    float offsetV = 0.0f;
    
    if(amplitudeU > 0.0f) {
      offsetU = amplitudeU * Mathf.Sin(scrollSpeedU * Time.time);
    } else {
      offsetU = Time.time * scrollSpeedU;
    }

    if(amplitudeV > 0.0f) {
      offsetV = amplitudeV * Mathf.Sin(scrollSpeedV * Time.time);
    } else {
      offsetV = Time.time * scrollSpeedV;
    }
    
    renderer.material.SetTextureOffset("_MainTex", new Vector2(offsetU, offsetV));
  }
}